Problem Description
- You have a validation txt file in the .well-known/pki-validation folder
- Visiting the URL http(s)://yourdomainDOTcom/.well-known/pki-validation/THE_FILENAME.txt results in a 404
- You have triple checked that the filename spelling is correct and exists in the file system
- Creating a test file within the .well-known folder works fine (like .well-known/test.txt)
Problem Resolution
Login to Plesk as an admin user. Head to Extensions and look for the Sectigo SSL extension and remove it. Then run a Plesk web repair to have it regenerate web server configuration files.
Once these steps are done the 404 error will be gone. This is a bug in the sectigo extension; it should not be used and does not need to be used if you're manually generating SSL certificates anyway.
