The problem may be with the aircraft, itself. I don’t own the CRJ550, so I’ll use the default Cessna Caravan as an example
Take a look at the file:
asobo-aircraft-208b-grand-caravan-ex\SimObjects\Airplanes\Asobo_208B_GRAND_CARAVAN_EX\aircraft.cfg
The aircraft is identified by ATC using these two lines:
atc_type = "TT:ATCCOM.ATC_NAME CESSNA.0.text"
atc_model = "TT:ATCCOM.AC_MODEL C208.0.text"
If you see “TT:”, that means, it’s referencing something in the locPak file. If you don’t have a “TT:”, then the system will take whatever hard-coded value they’re giving it.
If you’re using the sim in English, looking at the en-US.locPak file, the system will identify it as:
"ATCCOM.ATC_NAME CESSNA.0.text": "Cessna",
and
"ATCCOM.AC_MODEL C208.0.text": "Caravan",
If you own this aircraft through the Marketplace, it is possible that the aircraft.cfg file might not be there, as it would be encrypted. In that case, your only recourse is to open a ticket with Aerosoft, which you may want to do anyway, even if you do have access to the file, so they can make the change permanent. (Keep in mind that if you edit your aircraft.cfg file, any subsequent product updates may overwrite that file.)
Unfortunately, Flight Simulator doesn’t have a CRJ550 in their .locPak file. Only a CRJ700:
"ATCCOM.AC_MODEL CRJ700.0.text": "CRJ700",
"ATCCOM.AC_MODEL CRJ700.0.tts": "CRJ700",
So the most that Aerosoft could do would be to hard-code it on their side. Even if the did have a CRJ550 entry, I would have called it “CRJ”. "To say “CRJ 700” is too many syllables for fast-talking ATC.
You may want to open a Zendesk ticket with the Flight Simulator team asking for the addition of CRJ550 lines. However, I will caution that I have opened up somewhere around 400 Zendesk tickets and the team has fixed, I dunno, maybe ten of the bugs I’ve ever reported.
Hope this helps.