Sugestion: Upgrade Firefox to the latest stable version => www.getfirefox.com

There are many problems with webmail (especially gmail) lately. It can be caused by the AdBlock extension. If you have it installed here's what to do:

1. "Ctrl+Shift+F" Preferences (or right click on ADP symbol and choose preferences)
2. 'Filters' menu > "Update all subscriptions" 

Solution from https://support.mozilla.com/pl/questions/896267 by dmcritchie

Hi Pawiecki. Thanks for your reply. Unfortunately the problem is not totally solved. I downloaded and upgraded the latest Firefox and attended to ADP as you suggested. However, the procedure;

'1. "Ctrl+Shift+F" Preferences (or right click on ADP symbol and choose preferences)
2. 'Filters' menu > "Update all subscriptions" ' - made no difference.

On the other hand disabling ADP altogether now means I can access email content. This obviously points to ADP being the culprit, but I liked ADP (for obvious reasons) and am not happy at not being able to use it. Can you give me any indication of when (or if) Firefox/ADP might come up with a solution to this problem.

Thanks very much for your assistance thus far.

Interestingly; none of the other identical computers in the house are experiencing this problem.

It's not ADP, it's ABP = AdBlock Plus

AdBlock Plus itself doesn't actually block anything, it is the filters that do the blocking. Changing to a different filter subscription could fix that, or just figure out which filter is blocking what you want to see or load.

Each filter can be turned off by itself to eliminate problems like that. In ABP Preferences, look at the "Last Hit" column after loading (or re-loading) the page to see which filters were used to block items on that page - date & time. Selectively turn off the filters that were used last, to figure out which one is blocking what you want to see. Un-check Enabled to disable that one filter.

Then, contact the subscription list manager and report the filter that was causing your problem, so that can be fixed for everyone using that subscription. Contact Information is probably at the beginning of the filter listing in preferences.

! Please report any unblocked adverts or problems
! in the forums ( http://forums.lanik.us/ ) 
! or via e-mail ( easylist.subscription@gmail.com ).

Then again, if someone else reported that problem it will be fixed automatically the next time your filter subscription is updated, The update frequency is 5 days for the most popular filter lists. You can do a manual update from the Filters menu > Update all subscriptions in ABP preferences.

Hi Edmeister. Thanks for your input. Followed your advice and found that disabling: ~t-mobile.co.uk,~channel4.com,~amusingplanet.com,~apple.com,~sportsdirect.com,~burningcamel.com,~prosperitybanktx.com,~repubblica.it,~mail.google.com##.ads , allowed me to view contents once again. I am using something called 'fanboy' filter on ABP. I sent ABP a report highlighting the above filter(thingy-whatever; please forgive my ignorance) and hopefully this may also help others. Many thanks again Edmeister - and Pawiecki - for all your help.

This worked for me. Switch character encoding to Western from Unicode.

Good luck. : )