My scenario:
We have an AD domain named example.domain with a testing exchange server. Also we have our really exchange server named example.com hosted by another EMAIL service provider. Usually, when I set up outlook for account as user1@example.com, I just use auto-discovery, and it only find the exchange server outside according to the email. However, I set up a new computer over VPN, while I configure outlook, I still use auto-discovery for account user2@example.com, but it goes to our internal testing exchange server. when it pops up for credentials, I cancel it. It still can search outside server. after I finished, I opened outlook, first it ask for credentials of the outside exchange server. after I input the correct password, then it ask for internal exchange server credential also. so how can I let outlook just ask for outside exchange credentials only?