Hi Guys
We did an Exchange 2013 to Exchange 2019 coexistent upgrade. When I point the DNS to the Exchange 2019 Exchange server cell phone email stops working. If I am on the local network on wireless the phones work no issue. if I am outside the company or only on cellular the email stops working. While on the outside I can delete and re-add my email account to the phone. Computers and laptops work no issue.
what the heck am I missing?
Thank You