I fixed it. I did several things so I can't say exactly which one solved the problem. You must delete the contents of the cache folder (SPT>cache). In "user" you must also delete the contents of the "cache" folder (delete the JSON files, even inside the "bundles" folder; do not delete the "bundles" folder, just delete its contents). Also try installing SWAG again. I think that by clearing the cache and reinstalling SWAG the problem should be resolved. (Sorry if it reads strange, English is not my first language.)