Executive Producer credit keeps being declined

I have tried adding one of our Executive Producers to a title page and it keeps getting declined. There were three productions this person EP'd on back to back that I and the same Director and several other executives with the this EP's production company worked on. This was 20-years ago, so it is very difficult to locate production documents, but I still have a VHS copy of the project. Do I have to convert this to digital, photograph the credits, and post that as supporting evidence to get this credit processed? I would think that the other titles showing we all worked on these projects together for his ProdCo would be sufficient, but any help or advice is appreciated. (Edited to remove identifying info.)