Gitlab CE emails have invalid links

I have installed the Gitlab Community Edition, It’s working perfectly with the real domain. But Emails have invalid links like below.

http://url5324.MAINDOMAIN.com/ls/click?upn=GMz-2BK8Zd5W-2FWIV12nwK-2FtpZjFnJEtM00PnJdST3PeHxAARqVYtxh0dq1fZV6Zh7I3-2BlCou0CaptFtrfX4n20S2xWX7Wc0bnZIFpW-2BI3G0-2FL47qY1iRZuLihD4xjvcLJKPBrKu5j769mXJdMEIL3qUg-3D-3DD_1r_ED5UgBji-2BviGWW6kbG3yI8qItMuStFxx1CORFy7PU3So6H0o4hsJPv6IujRTu8fFsQBkmioEjpO8NkuzBPxnRBexzXdnxZmH9Q4K6ZJ1ebT-2Fw1SK-2BvDIzFGcB583b0JbHlLAJTiIvqWpjFFk-2BSvYZWGF-2BfEGq0mUe1JU-2FgDJpXAn8cDhEO9QydAyHEPqwtqjsavLLqqqefwsV9M9Th-2B8Ub4UetY7c98gCnIX3c0Ff3w-3D

But it should look like this

http://SUBDOMAIN.MAINDOMAIN.com/ls/click?upn=GMz-2BK8Zd5W-2FWIV12nwK-2FtpZjFnJEtM00PnJdST3PeHxAARqVYtxh0dq1fZV6Zh7I3-2BlCou0CaptFtrfX4n20S2xWX7Wc0bnZIFpW-2BI3G0-2FL47qY1iRZuLihD4xjvcLJKPBrKu5j769mXJdMEIL3qUg-3D-3DD_1r_ED5UgBji-2BviGWW6kbG3yI8qItMuStFxx1CORFy7PU3So6H0o4hsJPv6IujRTu8fFsQBkmioEjpO8NkuzBPxnRBexzXdnxZmH9Q4K6ZJ1ebT-2Fw1SK-2BvDIzFGcB583b0JbHlLAJTiIvqWpjFFk-2BSvYZWGF-2BfEGq0mUe1JU-2FgDJpXAn8cDhEO9QydAyHEPqwtqjsavLLqqqefwsV9M9Th-2B8Ub4UetY7c98gCnIX3c0Ff3w-3D