FTP Test Problems: too high wattage / resistance

Hello all,

I recently bought the Fenix 6x and wanted to conduct a Ftp test and proceeded as in the official description of Garmin. (Indoor Cycling -> Menu button -> Training -> Ftp test). After warm up phase the test started to apply already quite high resistance of 215-235 W for 4 minutes. After that intervall it was further increased and so on, until I wasn't able to pedal any longer before finishing the test. I manually decreased the set Ftp value from 200 down to 40 watts, but this didn't change the test. It again started with relatively high watt of 215 w. Is there a bug, am I doing something wrong or requires this test a certain level of  fitness and always starts at this wattage?

I would be pleased if you could help me to fix my problem.

Thanks and best regards,

Felix