This is not an error. This message is just an alert saying that a solicitor on the gift is currently not an assigned solicitor solicitor for the constituent. It is not necessary for a solicitor to be assigned to a constituent to add them to a gift.

If you want to go add that solicitor as an assigned solicitor to the constituent, click Yes to the message.

If you do not want to add that solicitor as an assigned solicitor to the constituent, click No.