screaming channels

Recently, I have a problem when recording, at random, the same channel I record into something like such a self-feedback and start screaming. Once I play with the inputs on f4-audio connections, it works out until next time. audio file of the problem— :arrow_right:

cubase 9.5 -64bit
MAC os x El Capitan 10.11.6
rme fireface uc400

tnx for help

Hi and welcome,

Is there any plug-in in DEMO/Trial mode by any chance?