When joining a system to a homegroup, you may receive the following error message "The password is incorrect", even though you have typed the password correctly.
This can be caused by a difference in the Date and Time settings on the computer trying to join the homegroup, and not an invalid password. If the date/time of the computer joining a homegroup is greater than 24 hours apart from the date/time of the system that owns the homegroup, this will cause the error.
Adjust the date/time settings on the system joining the homegroup, to match the system that owns the homegroup, and then try to join again.
In this scenario, the authentication certificate is treated as invalid due to the timestamp. The error returned is simply stating that the authentication failed.