Uncaught TYPO3 Exception: #1561445710 Could not acquire exclusive lock (blocking+exclusive)

[bh-teufels]

I use reddis Cache for femanager user registration an get following error if users has the same IP.
user get error "Too many attempts from this IP address. Try again later." in the frontend.
in Backend Error log it says "Uncaught TYPO3 Exception: #1561445710 Could not acquire exclusive lock (blocking+exclusive)"

Is there a security setting or something which limits the connections from one IP?
is it possible to deactivate or change the limit?

[bmack]

Maybe femanager uses locking as well, and should be less restrictive? The IP limitation definitively comes from that extension, not by distributed-locks