Situation: After enabling MFA, some users have a problem to access email from Android phone or your home computer. Whenever you enter the domain password, it keeps popup for the password.
Resolutions: 1. For the user, you may need to create a app password from office 365. Please refer to this page: http://www.howtonetworking.com/blog/2018/10/08/how-to-create-microsoft-app-password-in-office-365/
2. If the user is using Android phone, please try Microsoft Outlook app. Or download or install Google Authentication app.
3. For administrator, you can disable and re-enable MFA.
I tried that and it wasn’t accepting my app password in Outlook. I was able to get it working with the app password by following these steps:
If you typed your app password correctly as above link, please try to clean the window credential to check if the issue persists:
1. Type “Credential Manager” in the search box of computer > Click “Credential Manager”.
2. Click “Windows Credentials” > “Generic Credentials”, you will most likely see the entries about the email account of the user.
3. Delete them.
4. Restart outlook, you should type your app password again and select the option to remember it.
After performing those steps Outlook would accept the app password that was created.
I found those steps at:
https://answers.microsoft.com/en-us/msoffice/forum/msoffice_outlook-mso_win10-mso_o365b/app-passwords-not-working/fa9eaa6a-1ee2-4f45-a37f-6e13ca92a14e