Thanks for your confirmation, I think I find the issue, you are actually using a OpenAI Endpoint. Please see below screenshot, you should click on the three dots and click on Language Service in your AI service endpoints sub tab.
It should be https://XXXXX.cognitiveservices.azure.com/
I hope this helps, please let us know if you are still blocked.
Regards,
Yutong
-Please kindly accept the answer if you feel helpful to support the community, thanks a lot.