Temporary User can not unlock with the passcode

I am using UL3 BT(2nd Gen) for a vacation rental house.
It has been working just fine for about 1 year but suddenly the temporary user (guest) can not unlock with the passcode…
It seems it works on the chek-in day, but the next day it can not be unlocked anymore.
I checked with the temporary user’s schedule and how many times it can be unlocked but I had no problem with my settings…
Is there anyone experienced the same trouble.
This is very critical because our guest is locked out from the house…
Thank you for your advice!

I am not 100% sure what lock I have but I can tell you that my lock has done the same thing. It even doesn’t accept my fingerprints sometimes even though they are clearly stored.
I think it loses touch with the plug in device that connects to the wifi and then you have trouble. I love the lock when it works but am frustrated at the inconsistency.

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