![powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow](https://i.stack.imgur.com/xgAb5.png)
powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow
How to test SMTP using Opportunistic TLS with Powershell and grab the public certificate a SMTP server is using
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Mike Lee's BlogSharePoint, Exchange, Outlook and Hybrid Support BlogsTest email from SharePoint using PowerShell
![powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow powershell - How to fix 'the SMTP server requires a secure connection or the client was not authenticated' error when the server response was 5.7.0? - Stack Overflow](https://i.stack.imgur.com/A9fkI.png)