I am having the same issue. I try to open a Notion using Notero Extension and since I do not use Notion App I get this error. I had the option to initially set the app to open this link, but I can't get this query any longer.
This file does not have an app associated with it for performing this action. Please install an app or, if one is already installed, create an association in the Default Apps Settings page.
This file does not have an app associated with it for performing this action. Please install an app or, if one is already installed, create an association in the Default Apps Settings page.
For problems with a plugin, you'll need to contact the plugin developer.