Sorry Alan I have NOT had your problems BUT was going to ask IF you logged into Ancestry BEFORE trying to tree share–that is the way I usually do it BUT finally tried both tonight and both worked..
Have you tried deleting your browser history including cookies, deleting your computer cache , trying a different browser and RESET TREE SHARE under RM settings? MIGHT help–might NOT
I’ve only had this happen when I was in the wrong database BUT interestingly enough, I have the exact opposite problem today-- yesterday I disconnected from my Ancestry tree Jazz and uploaded a different tree ZIG-- could only access the new tree ZIG NOT the one I disconnected from-- so I eventually deleted the new tree ZIG I had just uploaded ( I was trying various options for someone else) and today when I hit Tree Share on the tree disconnected tree Jazz–it worked— then I went in and tree shared a new version of ZIG and it worked-- so now I have 2 trees connected to Ancestry tree share..
NOTE to everyone-- I only mentioned this abt the 2 databases to show Alan that Ancestry seems to be a little bit wonky lately-- we have discussed this issue before abt being connected to 2 databases at the same time and really don’t need to go back to it