We are running exchange 2019 internally at our company. All of the users on the domain have no issues with their email connecting to the server. However, if i try to connect to a mailbox from a PC that is outside of their network, it won't connect. An outlook login prompts me for credentials which i provide and eventually a microsoft sign in pops ups. I plug in my email address and it tells me that the username may be incorrect but it isn't. I went to the microsoft remote connectivity analyzer and it seems to pass with flying colors. Any thoughts would be appreciated.
