Error generating new OAuth password client

I am trying to connect my nextcloud server to nextcloud. but every time I try to generate a new password client, Iget an error:

There was an error processing your request, please try again at a later time.

I also get the same error when trying to make a client credentials client.

I have generated a pub-private key pair like it says JSON API :: SuiteCRM Documentation

I tried to run composer install but I did not have composer installed. I installed it, ran composer install, and I got error:

HP Fatal error:  Uncaught ArgumentCountError: array_merge() does not accept unknown named parameters in /usr/share/php/Composer/DependencyResolver/DefaultPolicy.php:84

Not sure where to go from here.