I seen some chat sites not configured to work with firefox. Have you tried other browser to see if the problem wasn't site related.

Yeah i tried with google chrome there is a problem with iframe loading as well

What kind of error page do you get? Is that a page send by the server or the Firefox erro page? Can you attach a screenshot? *https://support.mozilla.org/en-US/kb/how-do-i-create-screenshot-my-problem *use a compressed image type like PNG or JPG to save the screenshot ---- You can try these steps in case of issues with web pages: You can reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files. *hold down the Shift key and left-click the Reload button *press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux) *press "Command + Shift + R" (Mac) Clear the Cache and remove the Cookies from websites that cause problems via the "3-bar" Firefox menu button (Options/Preferences). "Remove the Cookies" from websites that cause problems: *Options/Preferences -> Privacy & Security<br>Cookies and Site Data -> Manage Data "Clear the Cache": *Options/Preferences -> Privacy & Security<br>Cookies and Site Data -> Clear Data -> Cached Web Content: Clear Start Firefox in <u>Safe Mode</u> to check if one of the extensions ("3-bar" menu button or Tools -> Add-ons -> Extensions) or if <u>hardware acceleration</u> is is causing the problem. *switch to the DEFAULT theme: "3-bar" menu button or Tools -> Add-ons -> Appearance *do NOT click the "Refresh Firefox" button on the Safe Mode start window *https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-using-safe-mode *https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History -> Show All History" or "View -> Sidebar -> History"). Using "Forget About This Site" will remove all data stored in Firefox from this domain like history and cookies and passwords and exceptions and cache, so be cautious. If you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note. You can't recover from this 'forget' unless you have a backup of involved files. If you revisit a 'forgotten' website then data from that website will be saved once again. *https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox