Each time I try and add a new Custom Filter by going to Project Settings > Board > Custom Filters I get the following error message. I need to get these created ASAP but seems to be a Jira issue? I've refreshed multiple times which doesn't do anything.

I've tried to create the filters by going to Menu > Filters > View All Filters > Create Filter which works but then it doesn't show on my board or backlog. Does anyone know how I can get the filter to show on the board? I've set the Viewers as the Project and Editors as the project. I have a sandbox project which has a option on the board for 'Custom Filters' but it doesn't on this project. Both are team-managed.