# Maximum active connection reached **URL:** \ **Category:** Ignition\ **Created:** [September 10, 2018, 12:52pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603 "2018-09-10T12:52:18Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 10, 2018, 12:52pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/1 "2018-09-10T12:52:18Z")
We are seeing this after only about 250 connections INFO | jvm 1 | 2018/09/10 08:43:32 | E [i.m.s.i.ProtocolProcessor] [12:43:32]: Maximum active connection reached. Connection refused, server unavailable. CId=mimic/mqtt/00251 How can we increase the limit? ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [September 10, 2018, 12:57pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/2 "2018-09-10T12:57:20Z")
Can you give us a little more context? What kind of connections are these? Something from the MQTT modules? ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 10, 2018, 1:01pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/3 "2018-09-10T13:01:51Z")
Yes, MQTT Edge module with trial license. Is that a limitation of the trial? ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [September 10, 2018, 3:26pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/4 "2018-09-10T15:26:01Z")
Paging @wes0johnson or anybody else who might know šŸ™‚ ---
**Author:** ![wes0johnson](https://avatars.discourse-cdn.com/v4/letter/w/7ab992/32.png) [@wes0johnson](https://forum.inductiveautomation.com/u/wes0johnson)\ **Post date:** [September 10, 2018, 4:54pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/5 "2018-09-10T16:54:55Z")
Yes - MQTT Distributor is limited in number of client connections. In trail mode - it runs as Distributor Plus which supports 250 clients. When licensed, it can be licensed as ā€˜plusā€™ or ā€˜standardā€™. As plus it will remain with a 250 client limitation, and as standard it will have a 50 client limitation. ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 10, 2018, 5:40pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/6 "2018-09-10T17:40:37Z")
Your page at [https://inductiveautomation.com/whats-new-ignition-edge](https://inductiveautomation.com/whats-new-ignition-edge) says Supported MQTT Servers The MQTT Distributor Module and any server compliant with the 3.1.1 MQTT protocol OASIS standard. By ā€œand any server compliant with the 3.1.1 MQTT protocol OASIS standardā€ I understand that there is an alternative to ā€œMQTT Distributorā€. Are there instructions to link with a server other than MQTT Distributor so that we can overcome this limit? We want to go to 10,000 connections, at the very least. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [September 10, 2018, 5:43pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/7 "2018-09-10T17:43:11Z")
You want [Chariot](https://www.cirrus-link.com/mqtt-servers/) ā€“ explicitly designed for deployments bigger than Distributorā€™s limits. It is not an Ignition module itself. ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 17, 2018, 2:13pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/8 "2018-09-17T14:13:13Z")
Ok, we are running with IBM MessageSight, and are trying to get to 10,000 EON nodes and are unable to do so. We have tried 3 times (each cycle taking about half an hour including bookkeeping, evidence gathering, rebooting Ignition, etc). So far 100% reproducible in the couple of times we tried. It failed at 7500, 8300+ and 4000+ nodes, so it does not appear to be a hard limit. This wrapper.log message seems to accompany the failure: > INFO | jvm 1 | 2018/09/17 09:59:38 | Exception in thread "Thread-22" java.util.ConcurrentModificationException > INFO | jvm 1 | 2018/09/17 09:59:38 | at java.util.HashMap$HashIterator.nextNode(HashMap.java:1442) > INFO | jvm 1 | 2018/09/17 09:59:38 | at java.util.HashMap$EntryIterator.next(HashMap.java:1476) > INFO | jvm 1 | 2018/09/17 09:59:38 | at java.util.HashMap$EntryIterator.next(HashMap.java:1474) > INFO | jvm 1 | 2018/09/17 09:59:38 | at java.util.HashMap.putMapEntries(HashMap.java:512) > INFO | jvm 1 | 2018/09/17 09:59:38 | at java.util.HashMap.putAll(HashMap.java:785) > INFO | jvm 1 | 2018/09/17 09:59:38 | at com.cirruslink.mqtt.engine.gateway.EdgeNodeManager.getAllEdgeNodes(EdgeNodeManager.java:84) > INFO | jvm 1 | 2018/09/17 09:59:38 | at com.cirruslink.mqtt.engine.gateway.EngineWorker.run(EngineWorker.java:136) > INFO | jvm 1 | 2018/09/17 09:59:38 | at java.lang.Thread.run(Thread.java:748) We have screenshots, videos, that we can share to diagnose this and of course can reproduce this any time. Everything seems fine on the MIMIC and MessageSight side (ie. 10k connections established and maintained). ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [September 18, 2018, 3:50am UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/9 "2018-09-18T03:50:46Z")
> [@uwe](#): > > ConcurrentModificationException That is almost always a bug. Good catch. ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 18, 2018, 6:03pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/10 "2018-09-18T18:03:50Z")
We can reproduce with 1000 nodes. Just a little harder. Typical race condition, looks like it. ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 19, 2018, 11:36am UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/11 "2018-09-19T11:36:34Z")
Is there a better place to report this bug? Once it happens, the MQTT client is dead, and it prevents us from doing further work. ---
**Author:** ![Kevin.Herron](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/kevin.herron/32/7259_2.png) [@Kevin.Herron](https://forum.inductiveautomation.com/u/Kevin.Herron)\ **Post date:** [September 19, 2018, 3:49pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/12 "2018-09-19T15:49:41Z")
Yes, reach out to Cirrus Link. Paging @wes0johnson šŸ˜‰ ---
**Author:** ![wes0johnson](https://avatars.discourse-cdn.com/v4/letter/w/7ab992/32.png) [@wes0johnson](https://forum.inductiveautomation.com/u/wes0johnson)\ **Post date:** [September 20, 2018, 4:05pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/13 "2018-09-20T16:05:16Z")
Yes - send a query to [support@cirrus-link.com](mailto:support@cirrus-link.com) and weā€™ll take care of it from there. I agree it looks like a bug. ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [September 26, 2018, 7:05pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/14 "2018-09-26T19:05:48Z")
Thanks. Itā€™s working well. See screenshot with 10,000 EON nodes connected to Ignition. ![](https://us1.discourse-cdn.com/inductiveautomation/original/2X/e/e913f5b1e0f8513410cc962fe4ba238a61777bbf.png) ---
**Author:** ![uwe](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/uwe/32/6039_2.png) [@uwe](https://forum.inductiveautomation.com/u/uwe)\ **Post date:** [October 18, 2018, 6:23pm UTC](https://forum.inductiveautomation.com/t/maximum-active-connection-reached/19603/15 "2018-10-18T18:23:05Z")
2000 EON nodes, 20k devices, 200k tags