Tried again this AM.  Same message.  However, I did solved my issue with this message.  Could have been 1 of 2 things or both.  My clients turned 65 in 2023 and did not apply for CPP.  Was trying to not to have CPP premiums calculated on their business income. Removed that.  Secondly when their rental properties carried forward, the one that was sold left the first address blank, had to move the remaining one up into that space.  Hoping this makes sense! Then it filed.