Hello Alice,
thanks for your your reply.
CPU is typo: correct is MK22FX512VMC12 in MAPBGA 121-pin package

I'm using Processor Expert Software 10.4

For building and debugging I work with iSystems winIDEA Software, though I think this is not important here.
Attached is the project so far. I just added to ADC1 the ADC1_DP1 channel which creates the error.
In general it seems that I have problems using ADC1. As you can see I also try to use ADC1_SE4b, ADC1_SE5b and ADC1_SE6b. All of these can be configured, but they don't work. Changing inputs doesn't have any effect.