Unable to setup email Account

While setting email account in notification it showing invalid usename or password

I am assuming your credentials are in fact correct. Can you make sure that from the ERPNext server (cloud or local machine?) the gmail server is reachable (name lookup)? Is the domain configuration correct?

I’m using an on-premise server, I’m facing the same issue.
Can you help me to sort this?

Thanks,
PK

Have you tried reaching the destination mail server/port from the ERPNext machine? I.e.

$ telnet your_mail_server 143

Use the ports as in your config. Is there a response?