Sky replacement tool suddenly stopped working

 hello

I am using a Mac OS X running Monterey with plenty of RAM memory. My sky replacement option has stopped working. I don't use it often so I'm not sure when exactly this happened but I suspect when change from big Sur to Monterey. The fault is that the sky seems to be activated after selection but apart from a slight change in the density of the colour nothing else happens except for one sky in the 'dramatic skies' option. If I move the 'scale' slider to the extreme right i.e. over 300 then I can see a moderately large window with  the sky I have selected visible. It certainly does not fill the complete area of the sky in the selected picture. It seems most bizarre because apart from that one sky option which does work all the others just do not. This  software had been working perfectly until this point. Any advice gratefully received