Being unable to log into the outlook application.I ran into this problem a while ago and wondered what to do about it. I managed to find a 100% working fix that is fast and easy to apply.
Press the windows key+r and open the run command. Run the “regedit” command. You can also simply search using the search bar, whichever is easier for you.
Now that you’re in the registry editor, use the left side navigation pane to go to the following folder:
**Note that 16.0 is for Office 2016 (Outlook 2016). If you’re using an older or newer version, the number will be a different number, as follows:
Outlook 2007 = \12\ Outlook 2010 = \14\ Outlook 2013 = \15\ Outlook 2016 = \16\
Delete all the keys inside that folder. It’s that simple and you will be able to open outlook again and will be prompted to log back in.