Chat transcript not being received on email after setting clients email server in Send Chat Transcript

We have setup a custom email for sending the chat transcripts to the users after live agent has finished.

We have added the email server details in the email channel and then selected the same email in the inbox module but now, we are not receiving chat transcripts after ending a chat.

Which variable you are using to generate a chat transcript.?

We are not using any variable. We are using the send chat transcript option in the inbox module.

Previously we were using the default email and the chat transcripts were getting delivered from

But clients wanted to use their own email, so they added their email server credentials in the email channel and we selected the same for sending chat transcripts inside the inbox module. But now, no emails are getting delivered to them.