Here you can view the frequent asked questions for Player Auctions, it might answer your question!

1. Why cant my players sell any items?

You will need a permissions plugin, and give them the permission pa.limit.<auctions>. For example: pa.limit.1 - can sell one item.
Please note if you're using power ranks, this permission WILL NOT work. You will have to use an alternative permissions plugin like LuckPerms or ask the developer of power ranks to fix effective permissions.

2. Can I edit/remove/add auction categories?

Yes, you can. You can go into the folder, /guis/category.yml and go to the bottom and manage the categories there.

3. Why can't I add empty lines to item descriptions?

There is a feature disabled by default the empty lines will automatically be removed in the description, you can disable this in the config.yml