Hi All
i have a environment in which there are 2 forests AD and exchange servers, all users from both Exchanges will be migrated to Single tenant. both Exchange servers all together have more than 250 domains. right now i am facing following Challenges in creating/migrating users/mailboxes.
Conditions - All users must be in On premises AD and mailboxes in Exchange Online
Problem 1 - every domain has info@domain.com email ID s, so all together we have 200 Info Id s alone, as a rule of thumb there cannot be same UPN in the Azure AD. so migration doesn't happen.
Problem 2 - for some email Id s i deleted On prem AD account and mailbox and created new new AD account on prem and allowed it to sync. after the synchronization i noticed that new user is created as info3453@domain.onmicrosoft.com instead of info@domain.com .
can someone help me to understand how exactly this works and how to migrate all mailboxes smoothly under this condition.