Multiple device admin codes

Just installed two Ubolt locks, one on outer door and one about 3 feet away on inner door. Trying to set things up in app, getting error on adding admin code to the second lock; is there a restriction against using the same admin code for two decives??

Not sure why you received no reply.
I have 25 devices, and they all have the same admin code. So that would not be a problem.
It must be something else.
(Also, I have multiple locks within 3 feet of each other)