Hi, could be a couple of things. What security software do you use ? If it as Avast or Avg or : There is security software like Avast/AVG, Kaspersky, BitDefender and ESET that intercept secureconnections and send their own certificate.

• https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message#w_avast-and-avg-security-products
• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can
• https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites
• https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message
• https://support.mozilla.org/en-US/kb/connection-untrusted-error-message
• http://kb.mozillazine.org/Error_loading_websites
• https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER

If you are running any of the above software please check their community forum for a work around.

Firefox's Tracking Protection feature : When it is blocking content in a page, a shield icon will appear at the left end of the address bar next to the padlock icon. This article has more info on managing this feature:

• https://support.mozilla.org/en-US/kb/tracking-protection

Please let us know if this solved your issue or if need further assistance.

No, I had already tried most of these fixes and on change. This problem did accrue after I had put the latest version of windows 10 and latest version of Firefox. I am not getting any error messages only that the screen goes back to the sign on screen like it is being blocked..

So, I guess you installed new Video Card Drivers then as I did not mention, but the ones you had had errors in them. That was going to be for later.

Ok, can you please do a uninstall and reinstall follow this please : uninstall Firefox. Then Delete the Mozilla Firefox Folders in C:\Program Files , C:\Program Files(x86) & C:\ProgramData Then restart system. Then run Windows Disk Cleanup. (Note: This should be Pinned and run Weekly, If never done below expect 10's of gig's) Then run it again and click the button that says Cleanup System Files. Note: your Firefox Profile is saved. But you should make a back up before you do :

• https://support.mozilla.org/en-US/kb/back-and-restore-information-firefox-profiles
• https://support.mozilla.org/en-US/kb/export-firefox-bookmarks-to-backup-or-transfer

Reinstall with Current Release Firefox 61.0.0 with a Full Version Installer

• https://www.mozilla.org/firefox/all/

Please let us know if this solved your issue or if need further assistance.

I uninstall FireFox, did a DiskClean up and then reinstall the lasted Firefox but T-Mobile.com still would not logon. The other Firefox was found in the Program files (x86) but when I reinstall it , the files went into the Program Files.

Jmcclelland9 said

I uninstall FireFox, did a DiskClean up and then reinstall the lasted Firefox but T-Mobile.com still would not logon. The other Firefox was found in the Program files (x86) but when I reinstall it , the files went into the Program Files.

This means the new FF is based on your O/S bit version not what version you want to install. So uninstall all FF versions and delete the Mozilla folder and then install the right bit version for your O/S and try again.

Firefox is showing under C;\Program Files because my computer is a 64bit but I did find out that T-Mobile is a third party site, could that be the problem that I need to make it have get unblocked someway so it will open in FireFox and/or Windows 10. And that might be what is blocking it from opening? For I am not getting amy error messages. And do I still need to use the 32bit FireFox software?

The problem is still not fixed. Could it be in the settings? Of firefox and/or t mobile or windows 10 that it will not sign on completely? I have a older computer with Windows 7 and the settings of firefox are the same so I just don't understand why I am having just a problem. And when I was using the same computer I am using now t mobile would signon with no problem.

Help

Jane

WESTEND I did put the Firefox back on for my computer is a 64 bit processor but still can not get in to T-Mobile. Did I need to do again because I was using it before? I don't know why because i was using firefox and Windows 10 and was paying my bill on the T-Molibe site before I did a clean Windows 10 and install the lastest Firefox onmy computer and I had to put the lastest AVG Internet Security and alwarebytes softwares when I was using the older one. I was always using FireFox (like the site) . All what I have read on the fourm has not helped me. So I am still needing help to get back to what I had when I first install Windows 10 and the old AVG with no problems. I knwo things change but I did't think I would not be able to signin to one website I was using before. Called T-Mobile with no help either, told meto connect you.

If you did a clean install and deleted the Mozilla folder and it's not working might want to check what A/V or Firewall program your using that could be blocking it. And if you use adblocker software that could be a problem.

Hi Jmcclelland, what happens when you try to sign in? For example:

• Form won't submit (submit button doesn't do anything)
• Can't submit because a form element or CAPTCHA is missing
• Error message when submitting
• Submission seems fine but site redirects right back to login
• Submission seems fine but get a blank page

Also, are you using this page:

https://account.t-mobile.com/oauth2/v1/auth

(The real address then has a ? and a bunch of parameters but that's the base address.)

Yes I am using that t-molibe signon. It has saved my id info so when I enter to go in to my account the site redirects right back to login with no error messages.

I am using Avg Internet Security 18.5.3059 and Windows 10 come with IWindows Defender but is now controlled be AVG . Not sure if it has a adblocker but I don't see anything that says that. I see where Firefos has a Thired party to block but I have it set on NEVER.

Could you try temporarily turning off the Web Shield feature for secure (HTTPS) connections? AVG is now similar to Avast, which is described in this article: How to troubleshoot security error codes on secure websites.

Does that make any difference?

Jmcclelland9 said

Yes I am using that t-molibe signon. It has saved my id info so when I enter to go in to my account the site redirects right back to login with no error messages.

Hmm, AOL isn't displaying a wrong password message, so it must be something else.

Could you check:

Allow third party cookies:

This article will get you to that setting: Websites say cookies are blocked - Unblock them

If you changed any settings, was there any difference in the results?