SNMPv3 error - Credential Not Applied Due To:usmStatsUnknownEngineIDs

Hi

I have a router that's was managed by NFA (Ver. 9.9.0, Build 9900) and everything worked fine.
I wanted to change managed interfaces list, so I deleted whole ruter from NFA (License Management -> Delete).
Flows keeped comming to NFA, it recognized the name but not all interfaces were shown. I tried to Disable/Enable SNMPv3 for that router (this worked few times before in other cases when NFA was showing wrong parameters) but now NFA does not accept credentials with message:
'Credential Not Applied Due To:usmStatsUnknownEngineIDs'.

SNMPv3 discovery works normal for other management software.

How can I completely remove that device from NFA database to try add it from fresh start?

br, Darijo