The transfer of jpg file is restricted by your account administrator

I get (in meetings in MY account) this message:

"The transfer of jpg file is restricted by your account administrator"

I've double checked everything.   Send files via meeting chat is on (I can do PDFs, but not JPGs).  I have set up a whitelist of these file types:  .jpg,.pdf,.png,.gif,.tif

I hate people who post questions on boards where the answer is easily researched, but I'm stumped.

Help!  Thanks in advance for your time.