Question:

Sandbox User email addresses are automatically appended with .invalid (previously @example.com) anytime a Sandbox organization is refreshed.

This is an automated change by Salesforce(SFDC). The mechanism is used to prevent spam notifications sent to Production Users from the Sandbox. But, it also changes the Vadmin user's email to be an invalid email address. 

How to make the Email Address of the Vadmin User in a New Refreshed Sandbox Be Valid Again?

Answer:

Adjust the email address for the Vadmin user by using the following steps:

1. Log in to the new refreshed Sandbox.
2. Go to the Detail page of the Vadmin user.
3. In the Email field, remove the .invalid and ensure that the email address ends in @sfmail.veevacrm.com.
4. Click Save.
5. A verification email is sent to the new email address to authorize the change.
6. Open a ticket to Veeva Support. A Veeva Support engineer clicks the verification link to complete the resulting verification steps.

Related Documentation:

SFDC Help Documentation:

• Email addresses in sandbox appended with '.invalid' after refresh
• Change the email address of a User