I'm using litematica for a very long time now and in last month I noticed an error - when I build with Easy Place Mode i can place a few blocks normally and then I have the message "action prevented by the Easy Place Mode" (it didn't happend to me earlier). I tried to fix it in settings but it didn't help me. I searched the internet and one person (link to reddit below) with the same problem and there were told that i need to set "pickBlockable slots" to all slots instead of normal 1,2,3,4,5. I changed it and it didn't help. I'm leaving screenshots of my litematica settings;

I'm playing on 1.19.2 and using v.0.12.5 litematica,
Thank you and sorry for my bad grammar (english is not my my main language).

https://www.reddit.com/r/litematica/comments/z923nu/problem_with_easy_place_mode_blocks_wont_place/

I had this same exact issues. My settings matching those in the screen shots above.

Easy place "use key" is a hotkey to bind. For some reason, was not bound for me.

Under 'hotkeys' search for 'easy'. Bind easyPlaceUseKey to 'Right click'

Example of what fixed it, for me: