Hello,

I reviewed this inquiry and see in the image provided that “Basic Authentication” is being used.

Please follow Option 1 in the following KB Document: 

Try setting Outgoing Server Encrypted Connection to TLS

We just went through this process - Not sure how it’s managed from a gmail account but for google workspace accounts you will need to either setup 2-Step Verification and from that screen create an App Password

or

From the system admin panel go to Security >Access and Data Control > Less Secure Apps and check the “allow users to manage their access to less secure apps”

Then on the users personal settings, you can skip 2FA off and under the security settings enable the less secure apps

Based on the error you’re getting - I’d guess the TLS setting on the outgoing server connection as mentioned above is the first issue

Thank you @Missy Main , @darylbowman and @kyle90 for your prompt replies. I did check out the steps as mentioned and found out that the Outgoing Server Connection was set to None. Upon setting it to TLS it worked.
Thank you once again.

I would also like to get some light on Outlook setup @Missy Main , @darylbowman , @kyle90 :
Similarly I have been trying out to make a connection to my outlook account. I would like to confirm whether the passwords to be entered is the one that we enter while logging into the account or a different one (like the 16 character app password is used for setting up Gmail). If different, how can I get one?

For now I have entered the password which I use while logging in & have the POP and IMAP enabled in the account. But still not able to setup the connection successfully.

Thank you in advance.

I’m guessing you’re getting this error due to ‘Basic Authentication’ no longer being supported (as far as I know) by either Microsoft or Google. You’ll need to follow the steps listed in the article Missy posted or the hints Kyle gave. They are relevant now, just not the answer to the original problem.