For running J!5.1 you must https://fabrikar.com/forums/index.php?wiki/update-from-github/ or include the new file manually https://fabrikar.com/forums/index.php?threads/joomla-5-1-and-fabrik-cannot-find-files-error.54473/post-285151 See also Announcements
Please see our announcement here.
JS errors in browser console? Strange filename, filesize, extension...?but once in a while
Do you have "Obfuscate Filename" set? or "Work in progress"?Filuploaded didnt find: p1gbpkgo896ji3u01p71hc1k4j4