In case you haven't already... When you have a problem with one particular site, a good "first thing to try" is clearing your Firefox cache and deleting your saved cookies for the site.

(1) Bypass Firefox's Cache

Use Ctrl+Shift+r to reload the page fresh from the server.

Alternately, you also can clear Firefox's cache completely using:

"3-bar" menu button (or Tools menu) > Options > Advanced

On the Network mini-tab > Cached Web Content : "Clear Now"

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

(2) Remove the site's cookies (save any pending work first). While viewing a page on the site, try either:

• right-click and choose View Page Info > Security > "View Cookies"
• (menu bar) Tools > Page Info > Security > "View Cookies"

In the dialog that opens, you can remove the site's cookies individually.

Then try reloading the page. Does that help?

In case one of your extensions is involved, could you test the site in Firefox's Safe Mode? That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

Not all add-ons are disabled: Flash and other plugins still run

After Firefox shuts down, a small dialog should appear. Click "Start in Safe Mode" (not Reset).

Any difference?

This appears to have worked. I don't understand Safe Mode so can you tell me what happens now I am in it? Do I have to reinstate Add-ons? How do I get out of Safe Mode?

Firefox's Safe Mode disables extensions, so you could review those and see which ones you can disable or remove for regular use. Open the Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then see what you can shut down. Since the McAfee extension strikes me as the one that is most likely to filter or block parts of sites, you might try disabling just that one and see whether it makes a difference.

(You might need to do this in "regular" mode if you can't use the Disable button in Safe Mode.)

Safe Mode also changes a few other things, but extensions are the most critical one.

Oh, to start Firefox in regular (not Safe) mode again, exit Firefox and start it normally.

OK only one more question! I have been using firefox and madasafish for ever (well almost) and McAfee for 7 years and this has only been happening for the last week or so. I guess I don't need t o know why!! After starting Firefox in safe mode and then closing it down and opening it again Webmail is now working ok in Firefox.

I just need to sort out why it's not working in IE11 now !! and fix that.

Thank you very much for your help

Also make sure that your security software isn't blocking the mail as you write that it happens in other browsers (IE) as well.

Boot the computer in Windows Safe mode with network support (press F8 on the boot screen) as a test to see if that helps.

• http://www.bleepingcomputer.com/tutorials/how-to-start-windows-in-safe-mode/