I have a big issue on all my Windows 10 desktop and Phone (insider and regular) mail app.
I log in on all my machines and phones with my main Microsoft account however the mail/calendar app on my Insider Phone and desktop and on my regular updated Surface 3 with Windows 10 today grab an alias as my main account in the Mail/Calendar app. :(
I had a little fix for it by adding my main MS account as a new account and deactivated the sync of email (turn off view calendar) but that doesn't always work. I get an error sometimes adding my main account.
How can I fix that the Win 10 on Desktop and Phone sees my main account I log in with on my devices as the main MS account in the Mail app?