Using Classic Outlook on Windows for personal email, calendar, and contact management
I am friendly user. I will try to provide possible information.
You said "I have just changed my hosting platform", did you setup again your email account on Outlook application in PC?
You can try to setup again your email account as one new profile and check the result. Overview of Outlook e-mail profiles - Microsoft Support, just don't delete any Outlook profile to protect Outlook data files.