SMTP Error Sending Email from J5 Server

[walterwood44]

Our site has a contact us form that allows a user to fill in their information and send it to us in via Gmail. We have been doing this for a very long time. Recently we started getting the following error message.

SMTP Error: Could not connect to SMTP host. Failed to connect to server

Initially I contacted our webhost, and they made some changes, and it worked for about a day. Since then, I have tried the following to get around this without success. This includes:

Double checking the Gmail account and password.
Using a different Gmail account.
Changing from Port 465 and SSL/TLS to Port 587 and STARTTLS.
Turning off 2FA.
Turning back on 2FA and using a Google App Password (including removing the spaces).
Using a different Gmail account with app password.

I considered having out host setup an email for us, but our domain is not with them but with Microsoft 365 that is not possible.

I created a log of the error but did not see anything I understood. I could post it, but it contains our URL and some customer information (they filled into the contact form).

At this point I have run out of ideas and need some help. Please be specific as I am not a developer.

[Per Yngve Berg]

https://help.protectedtrust.com/setup-s ... office-365

[toivo]

Does the button Send Test Mail in the Server tab of the Global Configuration work?

The problem could be caused for example by an issue with the SSL certificate of the web server. Did you use this tutorial to generate the log file: How to debug SMTP mail in Joomla 4?

I created a log of the error but did not see anything I understood. I could post it, but it contains our URL and some customer information

Edit the log file using an editor like Notepad++ and use its Find and Replace functions to redact the URL. Post the contents of the log file here for advice.