We were able to get this resolved, and it indeed was the extra slash at the end of the entity IDhttp://www.netsuite.com/sp/ By changing it to http://www.netsuite.com/sp this resolved the issue.

We were able to get this resolved, and it indeed was the extra slash at the end of the entity IDhttp://www.netsuite.com/sp/. By changing it to http://www.netsuite.com/spthis resolved the issue. Thank you very much @Bry Cabria-Oracle for your detailed response!