Help with filter no longer screwing in, piece broken

Hi gang, a little while ago when unscrewing the filter on my Divine hot tub, I noticed a small piece had come off that was still on the filter threads (see pics). Since then, any filter will no longer screw into the threads. Looking down into the hole, it seems strange that this tiny sliver of a ring would prevent that, but I guess it is? Anyone know the best way to glue this thing back so it's uber strong?

https://preview.redd.it/0l6810lroxzg1.jpg?width=960&format=pjpg&auto=webp&s=62bd60c3feb612589d1da7cbffed0fb21ed8673f

https://preview.redd.it/7tupu0iroxzg1.jpg?width=1280&format=pjpg&auto=webp&s=0de6c8cc4d45c9cdd5f1c0b8f40b7dd7bd92bf52

https://preview.redd.it/3e2ua0iroxzg1.jpg?width=960&format=pjpg&auto=webp&s=6c5352a36888444da22a2cc26465cc0d27560197