GroupMember endpoint with committees.

Hello,

We are trying to use the RESTful API on committees.

According to the documentation here:
https://developer.imis.com/reference/groupmember#getgroupmemberbyid

We should be able to retrieve a committee record as follow:
https://imistour2847.imiscloud.com
/api/GroupMember/COMMITTEE%2FAWARDS%3A194

Note: "COMMITTEE%2FAWARDS%3A194" being the GroupMemberId value for "COMMITTEE/AWARDS:20134"

The response is then an HMTL page with the message:
"An unexpected iMIS error has occurred. Please try your operation again; if you still receive an error, contact the system administrator."

Any idea what is going on there?

Thank you for your help.