# Certbot hangs on stopping server **URL:** \ **Category:** Help\ **Created:** [September 20, 2019, 8:43am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450 "2019-09-20T08:43:31Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![emran.bm](https://avatars.discourse-cdn.com/v4/letter/e/85e7bf/32.png) [@emran.bm](https://community.letsencrypt.org/u/emran.bm)\ **Post date:** [September 20, 2019, 8:43am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/1 "2019-09-20T08:43:32Z")
My domain is: dongap.ir / [dongap.com](http://dongap.com) I ran this command: sudo kill -9 27915 && sudo certbot certonly --standalone It produced this output: It hangs on cleaning challenges. The last log is: “DEBUG:certbot.plugins.standalone:Stopping server at :::80…” My web server is (include version): No webserver The operating system my web server runs on is (include version): Ubuntu 16.04 My hosting provider, if applicable, is: haio.cloud I can login to a root shell on my machine (yes or no, or I don’t know): yes I’m using a control panel to manage my site (no, or provide the name and version of the control panel): no The version of my client is (e.g. output of `certbot --version` or `certbot-auto --version` if you’re using Certbot): 0.31.0 ---
**Author:** ![JuergenAuer](https://sea3.discourse-cdn.com/letsencrypt/user_avatar/community.letsencrypt.org/juergenauer/32/26491_2.png) [@JuergenAuer](https://community.letsencrypt.org/u/JuergenAuer)\ **Post date:** [September 20, 2019, 9:00am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/2 "2019-09-20T09:00:21Z")
Hi @emran.bm > [@emran.bm](#): > > The last log is: “DEBUG:certbot.plugins.standalone:Stopping server at :::80… looks like you have a running webserver with ipv6, Certbot can't stop that webserver. Check your system and stop that webserver manual. ---
**Author:** ![\_az](https://avatars.discourse-cdn.com/v4/letter/_/22d042/32.png) [@\_az](https://community.letsencrypt.org/u/_az)\ **Post date:** [September 20, 2019, 9:26am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/3 "2019-09-20T09:26:00Z")
> [@emran.bm](#): > > The last log is: “DEBUG:certbot.plugins.standalone:Stopping server at :::80…” Do you know whether anything is bound to port 80 at the time when Certbot is hung? For example, is it listed by: ``` ss -tlnp | grep ":80" ``` This would be useful to distinguish whether the standalone server is still actually running, or whether Certbot has moved onto something else (but hasn't logged about it). One reason that the underlying `shutdown()` operation of the standalone server may hang is if there is a client connected to it who is not disconnecting. You could confirm this by running the following when it is hung: ``` ss -tn | grep ":80" ``` If there is a client connected, it should be listed by the above, and it would explain why Certbot would be hung: it is waiting for the client to disconnect before it stops the standalone server entirely. ---
**Author:** ![emran.bm](https://avatars.discourse-cdn.com/v4/letter/e/85e7bf/32.png) [@emran.bm](https://community.letsencrypt.org/u/emran.bm)\ **Post date:** [September 20, 2019, 9:31am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/4 "2019-09-20T09:31:37Z")
Tnx for your reply. Yes there are bound connections. 3 in STABLISHED state and 4 in CLOSE\_WAIT. What should I do? ---
**Author:** ![\_az](https://avatars.discourse-cdn.com/v4/letter/_/22d042/32.png) [@\_az](https://community.letsencrypt.org/u/_az)\ **Post date:** [September 20, 2019, 9:33am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/5 "2019-09-20T09:33:50Z")
Those are connections inbound to the local port 80 server, right? Where are the connections coming from? You might be able to deduce more information by adding a `-p` (process) parameter to `ss`. > [@emran.bm](#): > > What should I do? Unfortunately I'm 99% sure this is a Certbot bug. It should not wait indefinitely to drain unexpected client connections when shutting down the standalone server. I've reproduced it locally and I'm about to file an issue. The question is, where are those `ESTABLISHED` connections coming from? They're causing the problems ☹ . ---
**Author:** ![emran.bm](https://avatars.discourse-cdn.com/v4/letter/e/85e7bf/32.png) [@emran.bm](https://community.letsencrypt.org/u/emran.bm)\ **Post date:** [September 20, 2019, 9:37am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/6 "2019-09-20T09:37:17Z")
Here is the result of `ss -tnp | grep ":80"`: ```auto CLOSE-WAIT 2486 0 ::ffff:37.187.222.161:80 ::ffff:83.122.182.233:54781 CLOSE-WAIT 6812 0 ::ffff:37.187.222.161:80 ::ffff:185.158.151.229:41759 ESTAB 0 0 ::ffff:37.187.222.161:80 ::ffff:188.159.29.158:17329 ESTAB 0 0 ::ffff:37.187.222.161:80 ::ffff:93.117.96.229:20263 ESTAB 0 0 ::ffff:37.187.222.161:80 ::ffff:151.242.168.31:15991 CLOSE-WAIT 9729 0 ::ffff:37.187.222.161:80 ::ffff:46.51.72.31:15608 CLOSE-WAIT 1872 0 ::ffff:37.187.222.161:80 ::ffff:194.124.33.245:37386 ``` Although previous logs say that the challenges failed because they didn’t reach the server! ```auto certbot.errors.FailedChallenges: Failed authorization procedure. dongap.ir (http-01): urn:ietf:params:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching http://dongap.ir/.well-known/acme-challenge/12hUISBU3M2fQRZ1EE_Z1vuR1-7H8wF_ajIwcAehQP8: Timeout during connect (likely firewall problem) ``` I tried to `curl` the challenge url (when hung), from my pc; it says: `curl: (56) Recv failure: Connection reset by peer` ---
**Author:** ![\_az](https://avatars.discourse-cdn.com/v4/letter/_/22d042/32.png) [@\_az](https://community.letsencrypt.org/u/_az)\ **Post date:** [September 20, 2019, 9:46am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/7 "2019-09-20T09:46:20Z")
I’m not quite sure what you should do, other than `kill -9` the Certbot process. If those 3 `ESTABLISHED` connections stay open, so will Certbot . I’ve now filed the bug ([https://github.com/certbot/certbot/issues/7386](https://github.com/certbot/certbot/issues/7386)) but I can’t really think of a good workaround, other than using a real webserver like nginx or Apache (with `--nginx` or `--apache`) and not using `--standalone` mode. ---
**Author:** ![emran.bm](https://avatars.discourse-cdn.com/v4/letter/e/85e7bf/32.png) [@emran.bm](https://community.letsencrypt.org/u/emran.bm)\ **Post date:** [September 20, 2019, 9:47am UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/8 "2019-09-20T09:47:56Z")
Hmm. Killed certbot, and connections are gone… However thanks a lot for your care. ---
**Author:** ![emran.bm](https://avatars.discourse-cdn.com/v4/letter/e/85e7bf/32.png) [@emran.bm](https://community.letsencrypt.org/u/emran.bm)\ **Post date:** [September 20, 2019, 2:32pm UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/9 "2019-09-20T14:32:34Z")
Hi. I’ve no webserver running. ---
**Author:** ![system](https://global.discourse-cdn.com/letsencrypt/original/3X/c/a/ca6c06ea1ea201324bba7048c6841ce60236468d.png) [@system](https://community.letsencrypt.org/u/system)\ **Post date:** [October 20, 2019, 2:32pm UTC](https://community.letsencrypt.org/t/certbot-hangs-on-stopping-server/102450/10 "2019-10-20T14:32:36Z")
Closed on October 20, 2019, 2:32pm UTC This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.