Shogun Flame timecode issues

I was setting up a Atomos Shogun Flame with this unit. I noticed the recorder will only work with this unit at 29.97fps. I tried it at 23.98fps and 24fps and I received a “improper frame rate” message on the recorder. I made sure the recorder and this unit were set at the proper frame rates..eg. 23.98(both) 24(both) but nothing. I made sure the recorder had the proper firmware as per the support(Atomos) and my TC generator has the latest firmware. What could be the issue? Thanks