iCloud Reminders (CalDAV) sync says password is incorrect. I can’t log into 2Do.
If Reminders (CalDAV) sync was working fine for you and has suddenly stopped working, or it's reporting that the password is incorrect although you're entering the correct password, the following may apply to you.
If you're using Apple's new two-step verification method for your iCloud account, starting 1st Oct 2014, you will now have to issue App Specific passwords in order to use your account with 3rd party apps such as 2Do. So, if 2Do was working fine before, it will suddenly stop working and report that the password is incorrect starting 1st of Oct. You must then follow steps explained in the link below to setup an app-specific password for 2Do and use that from now on. This will apply to both 2Do on iOS and 2Do on Mac: