Example Email Address field missing

"I’m running ERPNext 15 on Docker using Frappe_Docker to build a custom image. I’m trying to set up the email domain, but the ‘Example Email Address’ box is not visible.

I’m expecting to see this box as shown in the docs.

This is what showing on my setup:

Is there any prerequisite to set before configuring the email domain?

For Domain configuration email id is not required.
Just give domain name and proceed.

It hangs and finally gives ‘request timeout’. I can confirm the email domain is working though. I’ll keep trying. Thanks.