That issue can be caused by a Corrupted Cookie that is too large (> 4 KB).

-> Tap ALT key or press F10 to show the Menu Bar

-> go Tools Menu -> Clear Recent History -> Time range to clear: select EVERYTHING -> click Details (small arrow) button -> place Checkmarks on Cookies, Cache -> click "Clear Now"

-> go to Tools Menu -> Options -> Advanced -> Network -> Offline Storage (Cache) section: click "Clear Now"

-> Click OK on Options window

Check and tell if its working.

Hi

I had managed to access to websites. No error msg shown. But after every 2 download files is done , I must clear the cookies history and re login to my account before I can download another 2 files.

Please help.

Thanks

Taken from https://support.mozilla.com/en-US/questions/759366

cor-el: If clearing the cookies doesn't help then it is possible that the file cookies.sqlite that stores the cookies is corrupted.

Rename (or delete) cookies.sqlite (cookies.sqlite.old) and delete cookies.sqlite-journal and cookies.txt, if they exist, in the Profile Folder in case the file cookies.sqlite got corrupted.

http://kb.mozillazine.org/Profile_folder_-_Firefox

http://kb.mozillazine.org/Cookies#Removing_cookies

Check and tell if its working.