Add item wrong request Error 404

I am new using Tainacan plugin. I tried to add new item but I received this error message.
Did I missed something in the setting or installing the plugin? Thank you

Hi @khanah, how are you? Welcome to our forum!

This error could appear in a variety of situations, it may take bit for us to debug and find the exact cause in your server. But let’s first try to cover the basics:

  1. Try updating your permalinks, as described here: Tainacan Wiki
  2. Take a look at your System Check page, to see if everything is fine there: Tainacan Wiki.
  3. If none of this gives you a light, provide us with details from your Browser console in the exact moment where the action generates this error. We have some instructions regarding this here: Tainacan Wiki