Hello! This has been an issue for a few months now. See if any of these solutions help.
- Try using a different verification method. On the login screen, click sign-in options and use a method other than your password.
- If you don't have another method, try adding the Authenticator... but to do so, you need a device with your email address linked to it, such as your cell phone. See the link below for how to add the Authenticator.
- Restart your modem; sometimes it's a network issue. Unplug the modem > Wait 60 seconds > Plug it back in.
A friend had this problem, and I helped him. There seems to be some kind of connection between Outlook and the Internet Service Provider (ISP). We had to contact the ISP.
A spam filter at the ISP, or at the modem, could be causing this... since the problem doesn't occur on another network.
If the problem persists, I recommend contacting your ISP. Replacing the modem may help.