Time to Review Use of Send-MailMessage Cmdlet with Exchange Online
Microsoft is in the process of removing TLS 1.0 and 1.1 support from Exchange Online to enforce the requirement to use TLS 1.2. It will take time before every mailbox server declines old TLS connections, but it’s going to happen. And when Exchange Online enforces TLS 1.2, it can stop PowerShell scripts sending email using the Send-MailMessage cmdlet via the SMTP AUTH protocol. Our script to send a welcome message to new users is a good example of the type which will be affected.
The problem occurs because the workstation where the script runs attempts to negotiate a TLS 1.0 or 1.1 connection for the SMTP AUTH protocol. Exchange Online uses opportunistic TLS to negotiate connections with mail clients and other servers. An inbound connection for SMTP AUTH can be serviced by any Exchange Online server, but after Microsoft upgrades a server, it will reject TLS 1.0 and 1.1 connection requests and only accept email if the sending server allows messages to be passed in an unencrypted form. PowerShell responds with the error “The SMTP server requires a secure connection or the client was not authenticated.” In this case, setting up the secure connection is the problem.
To be fair to Microsoft, they flagged this issue at Ignite 2020, noting in a supporting blog post that: “Both TLS 1.0/1.1 and Basic Auth are often used for SMTP AUTH. The deprecation of TLS 1.0/1.1 will break message submission for SMTP AUTH clients that continue to use it.”
Force PowerShell to Use TLS 1.2
The solution is to force PowerShell to use TLS 1.2 when it negotiates an SMTP AUTH connection to Exchange Online. This is done by running a command to select TLS 1.2 using the .NET ServicePointManager class. For example:
You can include the command in your PowerShell profile, and the setting will apply to all connections created during the session. It’s probably better to include the command in any script which uses the Send-MailMessage cmdlet.
The issue has been known for a while and other email platforms also insist on TLS 1.2 connection and use the same solution for PowerShell (here’s an example). Given the popularity of Office 365, Exchange Online’s new insistence on TLS 1.2 might create more of a fuss due to the number of scripts likely to be affected.
Send-MailMessage and Gmail
The advent of the problem caused me to look at using Send-MailMessage with Gmail. I discovered that you don’t have to specify TLS 1.2 (this may change in future). After turning off two-factor authentication for my account and allowing access to insecure apps for the account, this rudimentary code was enough to send a message via Gmail.
$EmailParams = @{
SmtpServer = 'smtp.gmail.com'
Port = 587
UseSsl = $true
Credential = 'MyGoogleAccount'
From = 'MyGoogleAccount@gmail.com'
To = 'Ken.Bowers@office365itpros.com'
Subject = 'Sending emails from Gmail with PowerShell'
Body = "Email is just Wonderful!"
}
Send-MailMessage @EmailParams
This is the kind of change that results in a two-line update in the Office 365 for IT Pros eBook. Because we update every month, our text covers topics and issues that no other book attempts to do. If you’re responsible for an Office 365 tenant, you should subscribe today.
It’s not odd. It happens when Microsoft wants to signal that they plan to remove a cmdlet so that people can phase out using the older cmdlet and replace it with a new one. It happened with the Search-Mailbox cmdlet. The difference there is that a replacement existed. No replacement has so far emerged for Send-MailMessage.
Yes, that’s what I meant: announcing a deprecation with no forward guidance. That’s unusual in general. It would be like announcing EOL for SfB before anyone had heard of Teams.
{"id":null,"mode":"button","open_style":"in_modal","currency_code":"EUR","currency_symbol":"\u20ac","currency_type":"decimal","blank_flag_url":"https:\/\/office365itpros.com\/wp-content\/plugins\/tip-jar-wp\/\/assets\/images\/flags\/blank.gif","flag_sprite_url":"https:\/\/office365itpros.com\/wp-content\/plugins\/tip-jar-wp\/\/assets\/images\/flags\/flags.png","default_amount":100,"top_media_type":"featured_image","featured_image_url":"https:\/\/office365itpros.com\/wp-content\/uploads\/2022\/11\/cover-141x200.jpg","featured_embed":"","header_media":null,"file_download_attachment_data":null,"recurring_options_enabled":true,"recurring_options":{"never":{"selected":true,"after_output":"One time only"},"weekly":{"selected":false,"after_output":"Every week"},"monthly":{"selected":false,"after_output":"Every month"},"yearly":{"selected":false,"after_output":"Every year"}},"strings":{"current_user_email":"","current_user_name":"","link_text":"Virtual Tip Jar","complete_payment_button_error_text":"Check info and try again","payment_verb":"Pay","payment_request_label":"Office 365 for IT Pros","form_has_an_error":"Please check and fix the errors above","general_server_error":"Something isn't working right at the moment. Please try again.","form_title":"Office 365 for IT Pros","form_subtitle":null,"currency_search_text":"Country or Currency here","other_payment_option":"Other payment option","manage_payments_button_text":"Manage your payments","thank_you_message":"Thank you for supporting the work of Office 365 for IT Pros!","payment_confirmation_title":"Office 365 for IT Pros","receipt_title":"Your Receipt","print_receipt":"Print Receipt","email_receipt":"Email Receipt","email_receipt_sending":"Sending receipt...","email_receipt_success":"Email receipt successfully sent","email_receipt_failed":"Email receipt failed to send. Please try again.","receipt_payee":"Paid to","receipt_statement_descriptor":"This will show up on your statement as","receipt_date":"Date","receipt_transaction_id":"Transaction ID","receipt_transaction_amount":"Amount","refund_payer":"Refund from","login":"Log in to manage your payments","manage_payments":"Manage Payments","transactions_title":"Your Transactions","transaction_title":"Transaction Receipt","transaction_period":"Plan Period","arrangements_title":"Your Plans","arrangement_title":"Manage Plan","arrangement_details":"Plan Details","arrangement_id_title":"Plan ID","arrangement_payment_method_title":"Payment Method","arrangement_amount_title":"Plan Amount","arrangement_renewal_title":"Next renewal date","arrangement_action_cancel":"Cancel Plan","arrangement_action_cant_cancel":"Cancelling is currently not available.","arrangement_action_cancel_double":"Are you sure you'd like to cancel?","arrangement_cancelling":"Cancelling Plan...","arrangement_cancelled":"Plan Cancelled","arrangement_failed_to_cancel":"Failed to cancel plan","back_to_plans":"\u2190 Back to Plans","update_payment_method_verb":"Update","sca_auth_description":"Your have a pending renewal payment which requires authorization.","sca_auth_verb":"Authorize renewal payment","sca_authing_verb":"Authorizing payment","sca_authed_verb":"Payment successfully authorized!","sca_auth_failed":"Unable to authorize! Please try again.","login_button_text":"Log in","login_form_has_an_error":"Please check and fix the errors above","uppercase_search":"Search","lowercase_search":"search","uppercase_page":"Page","lowercase_page":"page","uppercase_items":"Items","lowercase_items":"items","uppercase_per":"Per","lowercase_per":"per","uppercase_of":"Of","lowercase_of":"of","back":"Back to plans","zip_code_placeholder":"Zip\/Postal Code","download_file_button_text":"Download File","input_field_instructions":{"tip_amount":{"placeholder_text":"How much would you like to tip?","initial":{"instruction_type":"normal","instruction_message":"How much would you like to tip? Choose any currency."},"empty":{"instruction_type":"error","instruction_message":"How much would you like to tip? Choose any currency."},"invalid_curency":{"instruction_type":"error","instruction_message":"Please choose a valid currency."}},"recurring":{"placeholder_text":"Recurring","initial":{"instruction_type":"normal","instruction_message":"How often would you like to give this?"},"success":{"instruction_type":"success","instruction_message":"How often would you like to give this?"},"empty":{"instruction_type":"error","instruction_message":"How often would you like to give this?"}},"name":{"placeholder_text":"Name on Credit Card","initial":{"instruction_type":"normal","instruction_message":"Enter the name on your card."},"success":{"instruction_type":"success","instruction_message":"Enter the name on your card."},"empty":{"instruction_type":"error","instruction_message":"Please enter the name on your card."}},"privacy_policy":{"terms_title":"Terms and conditions","terms_body":null,"terms_show_text":"View Terms","terms_hide_text":"Hide Terms","initial":{"instruction_type":"normal","instruction_message":"I agree to the terms."},"unchecked":{"instruction_type":"error","instruction_message":"Please agree to the terms."},"checked":{"instruction_type":"success","instruction_message":"I agree to the terms."}},"email":{"placeholder_text":"Your email address","initial":{"instruction_type":"normal","instruction_message":"Enter your email address"},"success":{"instruction_type":"success","instruction_message":"Enter your email address"},"blank":{"instruction_type":"error","instruction_message":"Enter your email address"},"not_an_email_address":{"instruction_type":"error","instruction_message":"Make sure you have entered a valid email address"}},"note_with_tip":{"placeholder_text":"Your note here...","initial":{"instruction_type":"normal","instruction_message":"Attach a note to your tip (optional)"},"empty":{"instruction_type":"normal","instruction_message":"Attach a note to your tip (optional)"},"not_empty_initial":{"instruction_type":"normal","instruction_message":"Attach a note to your tip (optional)"},"saving":{"instruction_type":"normal","instruction_message":"Saving note..."},"success":{"instruction_type":"success","instruction_message":"Note successfully saved!"},"error":{"instruction_type":"error","instruction_message":"Unable to save note note at this time. Please try again."}},"email_for_login_code":{"placeholder_text":"Your email address","initial":{"instruction_type":"normal","instruction_message":"Enter your email to log in."},"success":{"instruction_type":"success","instruction_message":"Enter your email to log in."},"blank":{"instruction_type":"error","instruction_message":"Enter your email to log in."},"empty":{"instruction_type":"error","instruction_message":"Enter your email to log in."}},"login_code":{"initial":{"instruction_type":"normal","instruction_message":"Check your email and enter the login code."},"success":{"instruction_type":"success","instruction_message":"Check your email and enter the login code."},"blank":{"instruction_type":"error","instruction_message":"Check your email and enter the login code."},"empty":{"instruction_type":"error","instruction_message":"Check your email and enter the login code."}},"stripe_all_in_one":{"initial":{"instruction_type":"normal","instruction_message":"Enter your credit card details here."},"empty":{"instruction_type":"error","instruction_message":"Enter your credit card details here."},"success":{"instruction_type":"normal","instruction_message":"Enter your credit card details here."},"invalid_number":{"instruction_type":"error","instruction_message":"The card number is not a valid credit card number."},"invalid_expiry_month":{"instruction_type":"error","instruction_message":"The card's expiration month is invalid."},"invalid_expiry_year":{"instruction_type":"error","instruction_message":"The card's expiration year is invalid."},"invalid_cvc":{"instruction_type":"error","instruction_message":"The card's security code is invalid."},"incorrect_number":{"instruction_type":"error","instruction_message":"The card number is incorrect."},"incomplete_number":{"instruction_type":"error","instruction_message":"The card number is incomplete."},"incomplete_cvc":{"instruction_type":"error","instruction_message":"The card's security code is incomplete."},"incomplete_expiry":{"instruction_type":"error","instruction_message":"The card's expiration date is incomplete."},"incomplete_zip":{"instruction_type":"error","instruction_message":"The card's zip code is incomplete."},"expired_card":{"instruction_type":"error","instruction_message":"The card has expired."},"incorrect_cvc":{"instruction_type":"error","instruction_message":"The card's security code is incorrect."},"incorrect_zip":{"instruction_type":"error","instruction_message":"The card's zip code failed validation."},"invalid_expiry_year_past":{"instruction_type":"error","instruction_message":"The card's expiration year is in the past"},"card_declined":{"instruction_type":"error","instruction_message":"The card was declined."},"missing":{"instruction_type":"error","instruction_message":"There is no card on a customer that is being charged."},"processing_error":{"instruction_type":"error","instruction_message":"An error occurred while processing the card."},"invalid_request_error":{"instruction_type":"error","instruction_message":"Unable to process this payment, please try again or use alternative method."},"invalid_sofort_country":{"instruction_type":"error","instruction_message":"The billing country is not accepted by SOFORT. Please try another country."}}}},"fetched_oembed_html":false}
It’s worth noting that the command itself is deprecated, and with no apparent replacement! Isn’t that a little on the odd side?
https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.utility/send-mailmessage
It’s not odd. It happens when Microsoft wants to signal that they plan to remove a cmdlet so that people can phase out using the older cmdlet and replace it with a new one. It happened with the Search-Mailbox cmdlet. The difference there is that a replacement existed. No replacement has so far emerged for Send-MailMessage.
Yes, that’s what I meant: announcing a deprecation with no forward guidance. That’s unusual in general. It would be like announcing EOL for SfB before anyone had heard of Teams.