Dear All,
We are trying to send email notification using SMTP. But while doing test mail, we are getting this error message.

I never seen this before honestly. Is this anything we need to check in LCS?
This is we are facing in a project which is recently went live and they are using 10.0.10 version.
I have checked the outgoing mail server provided by the client and email and password what they have given is already configured in SMTP settings.
Any input will be appreciated.
Thanks.