Before anyone says it's my computer - please try it first with your own account please.  myemail.cox.net/ 

OP here.  On Firefox, going to https://myemail.cox.net/ goes straight to error message above.  On IE, I get the login screen, but after 30 seconds I get "Connection timed-out - reload."

In Firefox, I can go to Cox.com and login fine, but when I go to the "Cox email" link (which is simply https://myemail.cox.net/) , I get the same error message.  Same thin happens using IE.

OK, I downloaded Chrome, and it works fine.  But - it used to work fine on IE and Firefox too.  Can it be fixed?

I am having the same problem with the 404 error file not found. I've talked to support 4-5 times this week and they have no clue how to fix it and one told me to change providers, then said to call support. I use FF and also tried Edge but same error. If anyone can fix this please put info out here. Thanks.

Well, I tried clearing and rebooting again (did at least 3 times before), and now it works fine on FireFox.  IE still doens't work, but I don't really use that anyhow.  I also messed with the "Do Not Track" settings in Firefox, but put them back to how they were originally.  Not sure if that had anything to do with it.

By the way - I NEVER used MS Edge, but I just tried it for kicks.  It does NOT work (same problem).

I too was unable to access my emails, getting the same error the OP reported when using a bookmark. So i went to the Cox site and tried clicking on webmail from there, same error. I hopped in chat, was told to try a different browser, sure enough it worked in Chrome. Ok so its a Firefox issue. I asked the chat support if he could access emails in Firefox and he said they dont have the capability. HUH? He also wouldnt give me the link to the forums. Sigh.

I checked if Firefox updated recently and sure enough they released a high security update yesterday. So I went into Firefox Tools, Options, Privacy & Security and clicked on Manage Data under Cookies and Site Data. I then typed in Cox in the search box and clicked on Remove All Shown. Closed it out, retried emails and it worked.

I didnt have to reboot or close Firefox and I also run 3 addons (Adblock Plus, No Script and You No Cards) which had no effect on the situation as I turned them all off during testing. I turned them back on 1 at a time and made sure I could still access emails once the cookies were cleared and they didnt block anything. Im sure this is just a matter of Firefox forcing people to clear cookies for their high security update to be fully implemented.

I was able to access WebMail again on Chrome by clearing browsing data on More tools.

Same Issue please Investigate and fix.

I was getting an error message that it could not load, on my chromebook.

I had this problem for several days.  Cox was unable to find any issues with my account or the webmail url. It started working after several days - no explanation provided.

Edge on Android also not working, frequent error messages, spinning circles instead of email contents, page not loading and redirect to login page. Chat support was useless.

The year is 2021. Don't use Cox Webmail.