Identical problem... when I hit the sign-in button on att-yahoo.att.net, I don't even get to a userID prompt. all I get is:

An error occurred while processing your request.

Reference #97.e6472317.1616731254.33d5139a

An error occurred during a connection to login.yahoo.com. PR_END_OF_FILE_ERROR

Could you try clearing your Firefox web cache and deleting your saved cookies for the site.

(1) Clear Firefox's Cache

See: How to clear the Firefox cache (just web cache, not all site data)

If you have a large hard drive, this might take a few minutes.

(2) Remove your Yahoo cookies

While viewing a page on the site, click the lock icon at the left end of the address bar. After a moment, a "Clear Cookies and Site Data" button should appear at the bottom. Go ahead and click that.

In the dialog that opens, you will see one or more matches to the current address so you can remove the site's cookies individually without affecting other sites.

Then try reloading the page. Does that help?

You also could bypass any proxy that might be running by changing this setting:

• Windows: "3-bar" menu button (or Tools menu) > Options
• Mac: "3-bar" menu button (or Firefox menu) > Preferences
• Linux: "3-bar" menu button (or Edit menu) > Preferences
• Any system: type or paste about:preferences into the address bar and press Enter/Return to load it

In the search box at the top of the page, type proxy and Firefox should filter to the "Settings" button, which you can click.

The default of "Use system proxy settings" piggybacks on your Windows/IE "LAN" setting. "Auto-detect" can lead to a flaky connection. Change this to "No proxy".

Any difference?

Identical problem... An error occurred while processing your request. Reference #97.e6472317.1616731254.33d5139a

That is not the same problem. That kind of message is characteristic of a web application firewall completely blocking you from the site based on something suspicious about your request. Your IP address might be restricted, but you can easily test that by accessing the site in a different browser. Or you might have the privacy and blocking cranked up a little too much to the point that you look like a bot instead of a normal user. Please start a new question for this:

https://support.mozilla.org/questions/new/desktop/form

You can check the connection settings.

• Options/Preferences -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

You can remove all data stored in Firefox for 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 for this domain like history and cookies and passwords and exceptions and cache, so be cautious. If you have a password or other data for 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 for that website will be saved once again.

• https://support.mozilla.org/en-US/kb/delete-browsing-search-download-history-firefox

I followed the advice of jscher2000 and cor-el and thought the problem was solved. However, the solution proved temporary. Once again, I can't access Yahoo! Mail, Gmail or Google using Firefox. Other Bookmarks on my Bookmarks Toolbar work. I discovered this morning that, for example. sce.com can't be accessed using Firefox. Everything works using Edge.

Hi edrcpa, are you still getting the PR_END_OF_FILE_ERROR code, or has the code changed?

I'm getting the same error message as before when I try to access Yahoo! Mail. I get the same error message when I try to access Gmail.

You can check the server.

• https://www.ssllabs.com/ssltest/

You can check your browser.

• https://www.ssllabs.com/ssltest/viewMyClient.html

Cor-el, I don't know what to enter as the Host Name for the server test. I didn't get any error messages when I tested my browser, which is Firefox 87.0 (64-bit).

Sometimes when I Restart my laptop, the problem goes away. I just restarted my laptop and was able to access Yahoo! Mail using Firefox to reply to your message.

The problem started after the recent update to Firefox but the HTTPS Only feature doesn't appear to be the problem. I've already tried disabling that feature and that didn't solve the problem so I've re-enabled it.

The fact that your Firefox worked normally for a while suggests that your settings are okay. You could double-check that No Proxy is still in effect.

The suspect in this case is a proxy server or other "man in the middle" such as either a security software browsing filter or some kind of spyware/malware.

jscher2000, No Proxy is still in Network Settings.

Using Firefox, some web pages load instantly, others load very slowly and others won't load. Using Edge, the few web pages I've tested so far have loaded instantly.

I use security software which provides real-time protection and also scans my laptop every day.

I had been getting the same message:

    An error occurred while processing your request.
     Reference #97.e6472317.1616731254.33d5139a

This is what worked for me:

1) Go to History (Library - History). 2) Click on Manage History at the bottom of the list 3) Search for login.yahoo.com 4) Right-click on login.yahoo.com 5) Click on "Forget about this site" at the bottom

After the above steps, I was able to log in to Yahoo Mail.

Cor-el posted a dire warning about "Forget about this site." In the case of login.yahoo.com does that mean that I'd lose all my Yahoo! Mail folders and their contents?

There was another recent Firefox update. Since that update, Firefox can no longer access several other websites.

I've had to use Edge.

Cor-el posted a dire warning about "Forget about this site." In the case of login.yahoo.com does that mean that I'd lose all my Yahoo! Mail folders and their contents?

No, that data is stored on Yahoo's servers. The "Forget about this site" feature deleted data stored in Firefox files, not on websites.

There was another recent Firefox update. Since that update, Firefox can no longer access several other websites.

Still the PR_END_OF_FILE_ERROR error? If it's not a proxy, I wonder what is causing that. Is there any pattern to the sites you can and cannot access in Firefox?

Thank you, jscher2000.

I'm still getting the same error message: PR_END_OF_FILE_ERROR

I checked on https v. http but that's not the problem. Gmail Login is https but Google Search is http.

Now that you've reassured me that "Forget about this site" won't delete all my Yahoo e-mail folders, Contacts and Calendar, I'll try "Forget about this site." I'll try it first with a website such as IRS Forms and Publications which doesn't involve any saved information. http://apps.irs.gov/app/picklist/list/formsPublications.html is one of the "problem" websites.

I forgot to mention that I downloaded and installed Chrome. I had the same problem with Chrome as I'm having with Firefox. For example, I couldn't access Gmail using Chrome. I got the following error message:

This site can’t be reached accounts.google.com unexpectedly closed the connection.

This is kind of suspicious that something is blocking so many sites in multiple browsers. Let's think about the main links in the chain:

• browser ("No proxy" set)
• software intermediary: security software filter, parental control software ?
• operating system (No VPN)
• router
• ISP

If you haven't already, you might try turning your router off for 10 seconds and then starting it again, in case something is broken with its routing tables or some of its software crashed.

For your OS, try some malware scans if you can: Troubleshoot Firefox issues caused by malware.

This is baffling! My new laptop is a Lenovo ThinkPad X1 Carbon. I tried my old (almost 10 years old) Toshiba Satellite and everything works perfectly. I noticed that the URLs for the Home Webpage on my two laptops are different but changing that setting didn't solve the problem.

On my Toshiba, when I click the Firefox icon in my Quick Launch Toolbar, my Yahoo! Mail Inbox appears. I have Yahoo! Mail set to keep me logged-in on both my laptops.

On my Lenovo, I usually get the error message but sometimes I get the login-in page (NOT the Inbox) for Yahoo! Mail and that works but then, next time, I get the error message again.

I've now deleted the Firefox History for every website but that hasn't fixed the problem.

There is no parental control feature running.

The security software running is VIPRE (which is supposed to include a VPN), Malwarebytes Professional and SuperAntiSpyware Professional. All do scans in addition to real-time protection. This is true of both my laptops, although the VIPRE and Malwarebytes versions on my old Toshiba Satellite are different from those running on my Lenovo ThinkPad X1 Carbon.

I've asked VIPRE technical support about the VPN which is supposed to be a module of the current VIPRE security suite. I don't know how to tell whether or not the VPN is running. I looked a the background processes in Task Manager but I didn't see anything indicating that a VPN was running.

The operating system is Windows 10 Professional Version 20H2.

Spectrum serves my neighborhood for Internet, television and telephone. I very recently had to reboot the router because I lost my Spectrum television connection. That reboot didn't fix the Internet problem I'm experiencing.

I have the problem with Firefox and Chrome but not with Edge. Internet Explorer seems to have reached the point of being non-functioning.