This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

firefox 36 slow internet and server not found

  • 11 iimpendulo
  • 5 inale ngxaki
  • 2 views
  • Impendulo yokugqibela ngu CyberWolf64

more options

OK, I DO NOT have to do ANY of the NORMAL tricks to solve this. So, PLEASE do not tell me to reset, or alter anything. IT IS FIREFOX 36 ITSELF at fault. Previous verion was running smoothly. VERY smoothly. After updating to 36, it went downhill quickly. FIRST I am CONSTANTLY getting SERVER NOT FOUND errors, and SECOND the browsing speed is SLOW. Now, these WILL NOT HELP NOR ARE THEY AT ISSUE: Reset Firefox My addons My AV My Firewall My Profile THESE ARE ALL THE EXACT SAME as in previous version. THE ONLY DIFFERENCE is it is now Firefox VERSION 36. Something in 36 is seriously broken. And yes it is the browser itself NOTHING ELSE.

Sorry about all the caps, but I am angry. Previous updates everything was good. But as soon as 36 installed, no longer good. I am now going to see about downgrading to my previous version just so I can surf again in a smooth and wonderful fashion. IF, and it is a BIG if Firefox's NEXT update fixes these issues, I will be happy to upgrade again then. But I am VERY nervous about ever upgrading again. Now, IF there may be a NEW setting you put into 36 that could be screwing up my surfing, PLEASE let me know so I can change it. I will wait for a bit before doing a downgrade.

OK, I DO NOT have to do ANY of the NORMAL tricks to solve this. So, PLEASE do not tell me to reset, or alter anything. IT IS FIREFOX 36 ITSELF at fault. Previous verion was running smoothly. VERY smoothly. After updating to 36, it went downhill quickly. FIRST I am CONSTANTLY getting SERVER NOT FOUND errors, and SECOND the browsing speed is SLOW. Now, these WILL NOT HELP NOR ARE THEY AT ISSUE: Reset Firefox My addons My AV My Firewall My Profile THESE ARE ALL THE EXACT SAME as in previous version. THE ONLY DIFFERENCE is it is now Firefox VERSION 36. Something in 36 is seriously broken. And yes it is the browser itself NOTHING ELSE. Sorry about all the caps, but I am angry. Previous updates everything was good. But as soon as 36 installed, no longer good. I am now going to see about downgrading to my previous version just so I can surf again in a smooth and wonderful fashion. IF, and it is a BIG if Firefox's NEXT update fixes these issues, I will be happy to upgrade again then. But I am VERY nervous about ever upgrading again. Now, IF there may be a NEW setting you put into 36 that could be screwing up my surfing, PLEASE let me know so I can change it. I will wait for a bit before doing a downgrade.

All Replies (11)

more options

I have various Firefox installs and do not see any partcular problem with Firefox 36.

However I have been getting quite a few unexplained 503 errors. Often on the support site, and yet the servers seem to be ok from checking with status.mozilla.org. In may case it could be that the problem is unrelated to Firefox, I have not yet been concerned enough to do any serious troubleshooting.

One thing that is change with Firefox 36 and could conceivably be part of the reason you have problems is the ability to use HTTP/2 it is possible to turn that off for test purposes. Toggle the two prefs to false using about:config

  1. network.http.spdy.enabled.http2
  2. network.http.spdy.enabled.http2draft

I would advise against downgrading. I am sure whatever the problem there will be a solution or workaround that dos not need downgrading to an unsupported and now unsafe version.

This may of course be coincidence and down to some other change. I am not aware of any major faults or problems in Fx 36 having been found or reported.

more options

John99 said

I have various Firefox installs and do not see any partcular problem with Firefox 36. However I have been getting quite a few unexplained 503 errors. Often on the support site, and yet the servers seem to be ok from checking with status.mozilla.org. In may case it could be that the problem is unrelated to Firefox, I have not yet been concerned enough to do any serious troubleshooting. One thing that is change with Firefox 36 and could conceivably be part of the reason you have problems is the ability to use HTTP/2 it is possible to turn that off for test purposes. Toggle the two prefs to false using about:config
  1. network.http.spdy.enabled.http2
  2. network.http.spdy.enabled.http2draft
I would advise against downgrading. I am sure whatever the problem there will be a solution or workaround that dos not need downgrading to an unsupported and now unsafe version. This may of course be coincidence and down to some other change. I am not aware of any major faults or problems in Fx 36 having been found or reported.

Well, I tried turning off those 2 items restarted firefox, still same issue. As I stated, the ONLY change on system was update to v36 from v35.0.1. Literally everything else is exactly the same as I had it under 35.0.1. So, I am now looking at lists of changes/updates/fixes and so far not one thing even remotely rings a bell as a possible cause of this issue. And as to the idea of "other changes", there have been NONE. I am, pardon the expression, VERY anal about changes. And, yes I know you do not recommend a downgrade, but if this persists for much longer I may have no other choice. Except maybe giving up on FF and going to another browser. But that would not be made lightly as I really do like FF. A LOT.

more options

I am sure we should be able to make Firefox work for you. It works for me and for the majority of users.

Not an official Mozilla recommendation, but a useful test and workaround: Install the third party Firefox portable ESR (35.3). That will work ,and be a secure Firefox. (If the problem continues you will have proved it is NOT due to Fx36)

Install and test that. Confirm it works. Then afterwards we can try and sort out your problems with the Fx36 Release.

more options

You did not say if you had tried this;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select Network. Look for Configure How Firefox Connects and press the Settings button. Check the settings.


Some problems occurs when your Internet security program was set to trust the previous version of Firefox, but no longer recognizes your updated version as trusted. Now how to fix the problem: To allow Firefox to connect to the Internet again;

  • Make sure your Internet security software is up-to-date (i.e. you are running the latest version).
  • Remove Firefox from your program's list of trusted or recognized programs. For detailed instructions, see

Configure firewalls so that Firefox can access the Internet. {web link}

more options

OK, after much debate, I finally chose a more draconian technique. Since this all started AFTER the update, I backed up all important items and data using the FEBE addon. Then, did a COMPLETE removal of Firefox. A while back I had made the mistake when I had had issues with another update (quite a while back) created a new profile, which still kept all the alterations in about:config. I felt by removing everything completely and restoring to a fresh install everything BUT the configuration data it had to work. AND IT DID. No more problems.

more options

That was very good work. Well Done. Please flag your last post as Solved Problem so other will know.

And you can use Febe to restore your profile. Note: If the problem should return, go back and restore things one by one.

more options

Hi again CyberWolf64. Glad to hear a clean reinstall solved the problem. Thanks for posting back.


Points of information.

  1. Removing the program files but not the profiles is what we usually refer to as a clean reinstall. (Removal of the profile is optional, and more extreme; you will lose bookmarks passwords open tabs etc.)
  2. Using a new profile or using the Reset|Refresh both remove the preferences set by about:config
more options

John99 said

Hi again CyberWolf64. Glad to hear a clean reinstall solved the problem. Thanks for posting back.

Points of information.

  1. Removing the program files but not the profiles is what we usually refer to as a clean reinstall. (Removal of the profile is optional, and more extreme; you will lose bookmarks passwords open tabs etc.)
  2. Using a new profile or using the Reset|Refresh both remove the preferences set by about:config

As to your item #1, as I stated in my last post I backed up all important items using FEBE. It is the ONE addon I NEVER go without when installing FF anytime/anywhere. It has saved my butt more times than I can count.

But, now the BAD news. The speed issue is back BUT not nearly as bad. And I still get the occasional SERVER NOT FOUND error. So it looks like I will have to keep researching this issue some more and see if I can figure out recent addons that may be causative in nature.

And, I will create another thread for ANOTHER glorious issue that was an issue before the complete removal and still shows up. I have read about it on forum BUT NONE of the "fixes" mentioned do anything at all for it. Anyway, that is for another thread.

more options

I note you did open another thread on a new subject:

It is probably worth keeping an eye on another thread, and maybe subscribing to it:

Speed issues are not easy to troubleshoot, and could be because of connection problems or an overloaded pc for instance. They may also result in connection attempts timing out.

more options

Note Firefox 36.0.1 is out and that includes another fix for a problematic Fx36 change. Does that with either of your problems.

more options

John99 said

Note Firefox 36.0.1 is out and that includes another fix for a problematic Fx36 change. Does that with either of your problems.

OK, I have been updated to FF 36.0.1 for a bit, and SO FAR the Server Not Found has NOT yet happened. Speed is I am beginning to believe maybe leaning towards my service provider, possibly.

Will keep you posted.