I finally did that - deleted the whole Contao Manager Folder - and updated to 1.10.3. Still the same, always a 404 error. Can't update any packages....
Yeah, I ran into something similar with Contao 5. I had a variant template for a content element sitting under my theme folder and was scratching my...
Download the contao-manager.phar again (do not rename the file!), (FTP) transfer the contao-manager.phar to the online webspace and save it into the...