Settings empty

The right hand side of the settings stay empty. I can see tabs on the left hand side, but no matter what option I choose, nothing happens.

See below for console error

Uncaught Error: No select2/compat/dropdownCss
at callDep (select2.js?ver=6.1.1:209:19)
at req (select2.js?ver=6.1.1:370:20)
at select2.js?ver=6.1.1:184:24
at Defaults.apply (select2.js?ver=6.1.1:4443:27)
at new Options (select2.js?ver=6.1.1:4681:29)
at new Select2 (select2.js?ver=6.1.1:4808:20)
at HTMLSelectElement. (select2.js?ver=6.1.1:5341:26)
at Function.each (jquery.min.js?ver=3.6.1:2:3003)
at s.fn.init.each (jquery.min.js?ver=3.6.1:2:1481)
at $.fn.select2 (select2.js?ver=6.1.1:5338:14)