DELETE.

First of all, definitely contact your hosting provider support, as there might be an issue on their side, or they might have introduced some changes. Next, can you provide some screens or output from the autodiscover test in Outlook?

If you are using O365 and have an account there, what might happen is that Outlook tries to "connect to O365 as priority", which is a behavior you can control via the reg keys detailed here: https://support.microsoft.com/en-us/help/3211279/outlook-2016-implementation-of-autodiscover

This step is only available on 2016, so might as well explain why 2010 works fine.