I recently had an issue where a TM1 report would not work.
After looking closer I found it would not run the vba code Activecell.Calculate
After a bit of playing around I found that if I turned off
Tools > Options > Calculation > Iterations
everything would work as normal.
Personally I have never found a use for iterations in TM1 reporting and I think its worth turning offon any TM1 excel report.