You have provided no evidence of the issue and also nothing showing that the urls work in other browsers. I get the same error in chrome and Firefox. see screenshots The top domains work fine, but you should provide steps to get the urls you provided.

After doing a google search of the site up.nic.in, I found this for font converter. see screenshots Is this the converter you're looking for? https://vaad.up.nic.in/Convert_Unicode.html

For mp.gov.in, peb... Is PEB for Professional Examination Board? If so, how do you get to it from the homepage? I clicked on several links from my google search and they all failed. see screenshot

I found it. see screenshot

Dear sir, 1. https://peb.mp.gov.in/ 2. http://updes.up.nic.in/esd/font_converter/index.html

Above Useful & Important websites are not opening in my Firefox browser from last 10-15 days. They are working fine in other browsers like chrome & edge. i tries everything like refresh Firefox, Clear Cookies, Clear History, Clear site data etc. but nothing works for me. Please resolve this issue as soon as possible.

Are you at home or in the office? Can you provide steps to get to the urls from their home pages?

Access denied. see screenshot I clicked several links and they all fail. Doesn't appear to be a browser display issue, but more of access issue and I would guest the sites are made for Chromium browsers. Someone closer to dev will have to chime in. This is far as I go with this "issue" because the site times out.