@MildDisaster
Just ran into something similar myself. Here is what worked for me. Based on your error message, you have an orphaned frontend from and old HAProxy installation. Foolproof way to fix is to reinstall HAProxy, then browse to the frontend configs. Delete the old frontend config. Check System: Trust: Certificates and remove old certificate. Uninstall HAProxy. Done :) Hope this helps.
Just ran into something similar myself. Here is what worked for me. Based on your error message, you have an orphaned frontend from and old HAProxy installation. Foolproof way to fix is to reinstall HAProxy, then browse to the frontend configs. Delete the old frontend config. Check System: Trust: Certificates and remove old certificate. Uninstall HAProxy. Done :) Hope this helps.