How do I download and install update

Trying to update PSE 2020 Version 18 to Version 2020.1 and unable to download on my Mac, Big Sur. When I click on update now, I get the following message:

There is no application set to open the URL auphd://update?sapCode=PSE&baseVersion=18.0&platform=osx10-64&skipUpdateInfo=true.

PSE 2020 is installed on my Mac, so I dont know what App this message is referring to. Can someone please tell me what I need to do? Thanks in advance. Gloria