ManuTheCoder Incognito mode allows you to visit your site without cookies, history or cache, so I'd simply try that before I erase everything. The best would be to just try using another browser you have installed, eg. Edge. If it works, then the issue is with the browser.
lakshya I have found the error log at your forum and I'll report it to the extension authors
Edit: It seems like it already happened before, so the authors are aware of it: https://discuss.flarum.org/d/33038/147
We can't help you with fixing errors related to extensions, because we do not maintain them. All I can do for you right now is disable the extension, so your forum works again