@Torsten23 

it sounds like a cable fault, try connecting the EAP to the switch with a shorter cable to test, if it's ok it should show 1000 MBps

Use a standard rj45 patch cable to test .

  @shberge 

Have already tested the cable with a cable tester, everything ok. 1-8 incl. ground. Furthermore, I connected my laptop to this connection or cable and there I have the 1000Mbit. So the Cat7 cable should be fine.

  @Torsten23 

Ok, so if you are 100% sure that the cable is ok then there is probably something wrong with your device, so I would replace it with another one.

You can also try to force to 1000Mbps on the switch port to see what happens, either it switches to 1000Mbps or you lose the connection to EAP.

  @shberge 

So I just tested it again with another Cat 5e cable, but with exactly the same result! How can I force the port on the switch to 1000Mbit???

  @Torsten23 

If you only get 100Mbps on a new cable, it seems that there is a fault with the EAP,
But try locking the port to 1000Mbps

go to switch, ports, select the port you want to change  pres edit, select Profile Overrides. then you wil see this.

  @shberge 

Sorry I can't find this function as in the picture? Where can you see that again?

  @Torsten23 

okay habs

  @shberge 

Ok, found it and will test it ;-)

  @shberge 

Great now it worked. And 1000 Mbit are displayed. see image.
One more question, the changeover to 1000Mbit on the switch then probably applies to all ports, right?