I changed network providers from spectrum to frontier. I entered new mail server settings in Outlook (2016) and I get: Something went wrong and Outlook couldn't save your account settings. Please try again.

The server settings had been okay (with frontier) for several months, but last night outlook reverted to my spectrum mail server settings, and I haven't received any emails since 10:44 last night. What can I do? I can't upgrade to a newer version.