Unable to send a test mail from jenkins mail

I am unable to send the test mail from email plugin. I am getting the below error msg, Could anyone please suggest a solution on this?

As I am new user to community, Jenkins not allowing more than 1 image to share. This is the configuration I did.

You have a firewall that blocks the traffic maybe?

when I tried to send mail through cmd(using telnet), It’s working.

maybe you need to enable TLS so it uses secure communication instead of running on port 25

Not working, I tried with TLS also

Looks like you need to setup authentication for your email server. This is done by adding a credential with the username/password and then specifying that credential in the configuration for the mail server. It says right in the debug that “need username and password for authentication”

Credentials are provided, please see the screenshot in above conversation. Earlier it worked for me suddenly it was stopped working(seems to be an network restricted issue in the organisation). This is the log image of during working time.