Trouble with Outlook Desktop

Hi

I can log into the web browser Outlook and access my account. However I can't access it via the desktop.

It thinks my private email is a "school or business account". In error messages it tells me that my email does not exist in "tenant 'Microsoft Services"

When I've tried the "Run" program as per one of the options to address the profile issue ....I get a message saying " Windows cannot find 'Outlook.exe'.

Similarly when I use "Microsoft Support and Recovery Assistant" i get a message "outlook isn't installed on this computer" that is false!

Any assistance would be gratefully appreciated