Bad Omen Triggered Raids do not begin

I have a raid farm set up (raids induced in any of my other villages work), but I get the bad omen and go to my farm the raid bar loads about 99%, then it disappears.  This has been repeated 10 times and the result is always the same.  Other Mobs can spawn on my island with no issues, it is just the raids that fail to load.  All blocks on my farm are solid blocks none are water logged.

 

please help