Is the web page apart of telegram? If it's using an apk like Chrome or Samsung internet try going into the setting of the internet app and clear defaults because it sounds like you set a browser as default.
I would just check all your defaults to see if you can find it
Setting>apps>3 Dots top right (default apps)>set as default.
You should then have a list of your phones default programs. If you can't find anything inside of there you might want to delete and reinstall the app.