Its uncommon issue that e-mail clients does not work after server migration, here we will try to diagnose and fix any e-mail problem.
Before we start, its important to know that website migration between servers will not change your settings like passwords.
First we need to be sure that your domain name is pointing to the new server correctly, to do that, check your website in the browser, if your website is completely down or show "This Site Has Been Moved to a New Server" message then your domain is still pointing to the old server and it is normal for e-mail to stop working in this case. So we have to make sure that your domain is pointed to the correct server before checking any e-mail issue.
If Website is loading correctly from the new server and e-mail still not working, then you may need to update your mail client settings.
Usually what you need to update is incoming and outgoing mail server settings only, user name, passwords and ports will not be changed.
To update incoming and outgoing mail server settings in outlook, follow this steps:
1. Click on fire menu:
2. Find the mail box you want to reconfigure and navigate to server settings:
3. Change the incoming server name to mail.yourdomain.com or just domain.com, We presume that e-mail was working before the migration so nothing else have to be changed, but you may also review other settings to match the settings below:
4. And do the same for the outgoing mail server and use mail.yourdomain.com or just domain.com
Same settings can be adjusted in any mail client software on desktop or mobile, you may search the help docs of your software for how to find the settings area and use the above settings.
For the advanced users with special setup, you can use the new server host name instead of mail.domain.com or domain.com.