hello selonia59, do you use a useragent masking/hiding addon?

No. I do not have any add-on at all. Since it was not working, I have uninstall and reinstall from scratch FF but to no avail. So what I have on my mobile a basic Firefox without anything added to it. I have added a screenshot of my mobile.

Hello there,

Can you enter "about:config" into the address bar, search for "general.useragent.compatMode.firefox" and make sure that is set to "false" https://support.mozilla.org/en-US/questions/998087

Hope this helps!

general.useragent.compatMode.firefox is set to false... The problem remains a mystery.

I have the same problem on my LG g2 4.4.2 Firefox 33.0

Hello there,

Furthermore, in preferences reset all entries starting with: general.useragent

Keep us posted!

Hello Alex,

Have you tried any form of troubleshooting yet? Tell us about the results too.

All keys reset... quite a job... there is a lot of them!!! But nope, Firefox still forbids to install any add-ons at all. I am quite at a lost here. It just happened overnight probably following an update or something 'cause it was working fine and I had no trouble installing anything. Then one day, all my add-ons were gone and I cannot install back any of them. It's a shame because the strength of Firefox is actually the possibility to customize it with add-ons... If a solution is not found, I will have no choice but to pick another browser, I guess.

I've checked everything already and that is why I posted this problem here because this forum is my last resort to solve this mystery.

what useragent information is shown when you visit http://browserspy.dk/useragent.php on your device?

ok, here is what I have: UserAgent from header: Mozilla/5.0 (Android;Mobile;rv:33.0) Gecko/33.0 Firefox/33.0 UserAgent from Javascript: same as above Browser string: Mozilla/Netscape 6.x Operating system: unknown Browser name: Yes - version Firefox Browser version: Yes- version 33

Hope this helps!

I find it strange that the OS is unknown... By clicking on another link below, I've got this info: OS detected : Linux armv71

everything looks fine there & as expected there.

it appears this issue might be a problem on the addons server after all, mozilla's developers are looking into this: https://bugzilla.mozilla.org/show_bug.cgi?id=1083704

I think I might have found a workaround... Instead of going to the add-ons page from the app, I went to Firefox website where all add-ons are there and not only for mobile. I tried to install Bluhell and to my surprise, it was available!!! I've downloaded and installed it and it works!

The problem seems to come from the app itself. I've just installed another addon and it works. The trouble is, all addons are not filtered for mobile so you have to work your way through all of them and find out if it is compatible with your device or not but at least it works!!!

I didn't see your last post philipp but that would make sense that the problem comes from the addons server. If I try to access it through the app itself, it won't work and it still does. On the other end, if I go directly to the addons page in the browser, it works.

thank you for reporting back with your findings!