Does this issue occur on other browsers <i>(Google Chrome, Internet Explorer)</i>?

Not the sort of thing it is easy to help with as by definition it will not be a public site but one for Indian Taxpayers, and can be expected to be secure. Have you tried using Internet Explorer. You could try attaching screen shots of the problem pages and any error messages, but please be careful and edit out any confidential or sensitive information before attaching such an image. Please remember you are posting on a public and websearch indexed website, this is not a private support ticket. *link is https://support.mozilla.org/en-US/questions/968557 Are you seeing a shield icon in your location bar as explained in this article * How does content that isn't secure affect my safety? That is rather a longshot as it is a change in Firefox so could affect you this year, but would not have affected you last year. * see [[How does content that isn't secure affect my safety?]] I note the public portion of the site * https://incometaxindiaefiling.gov.in/ * talks about 'e-Filing' and 'Option 1: Use Digital Signature Certificate (DSC)' and then gives two other alternatives Other possibilities *[[Troubleshoot the "Secure Connection Failed" error message]]