Frontend error after updating to J4

Hi

I am trying to migrate a site to J4 and found that the front end gallery management page just displays a spinner when I click on an album. The console displays an error:

/admin-menu/index.php?option=com_droppics&task=gallery.ajaxCheckExitGallery&id_gallery=222  404 Not found

It appears to be related to URL rewriting because if I turn it off or move the menu item to the root the page loads correctly.

Any suggestions please?

Best regards
Trevor

Droppics Version 3.2.36
PHP Version 8.1.15
Web Server LiteSpeed
Joomla! Version Joomla! 4.2.7