# OPCUA Server Quick Client Reads but cant subscribe **URL:** \ **Category:** Ignition\ **Created:** [February 22, 2021, 11:15pm UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702 "2021-02-22T23:15:03Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![nbrown](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nbrown](https://forum.inductiveautomation.com/u/nbrown)\ **Post date:** [February 22, 2021, 11:15pm UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/1 "2021-02-22T23:15:03Z")
Please help. I have multiple micrologix 1400 devices that are subscribed to just fine, but I have one micrologix 1400 that the boolean values (and only the boolean values) can be read from the device in the quick client, and they read fine but they cannot be subscribed to (returns bad, unspecified). I’ve restarted the OPC module, deleted and reconnected the micrologix 1400, made sure that the binary values are global,… I’m at a loss. Any suggestions? ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [February 23, 2021, 12:22am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/2 "2021-02-23T00:22:49Z")
This is an obvious use of fault finding question powers! 😀 1. Did this problem just start, or has it always happened? 2. If it just started, then what changed? 3. What is the same about the systems that work? 4. What is different about the system that doesn’t work? But that’s about my limit. I touched a micrologix once several years ago, but that’s all I know about them. ---
**Author:** ![nbrown](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nbrown](https://forum.inductiveautomation.com/u/nbrown)\ **Post date:** [February 23, 2021, 12:24am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/3 "2021-02-23T00:24:45Z")
Just started from what I can tell. Nothing changed. The systems that work have the same exact settings. the only difference about this micrologix is the device itself. ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [February 23, 2021, 12:25am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/4 "2021-02-23T00:25:43Z")
Does the magic power cycle work? ---
**Author:** ![nbrown](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nbrown](https://forum.inductiveautomation.com/u/nbrown)\ **Post date:** [February 23, 2021, 12:27am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/5 "2021-02-23T00:27:04Z")
First thing I did. ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [February 23, 2021, 12:28am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/6 "2021-02-23T00:28:39Z")
Anything funny in the Ignition log files? ---
**Author:** ![nbrown](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nbrown](https://forum.inductiveautomation.com/u/nbrown)\ **Post date:** [February 23, 2021, 12:30am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/7 "2021-02-23T00:30:07Z")
nothing that I’ve been able to identify. ---
**Author:** ![peter](https://avatars.discourse-cdn.com/v4/letter/p/278dde/32.png) [@peter](https://forum.inductiveautomation.com/u/peter)\ **Post date:** [February 23, 2021, 12:31am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/8 "2021-02-23T00:31:02Z")
Unfortunately you’ve exhausted my skillset. Sorry I can’t help. ---
**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:** [February 23, 2021, 12:43am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/9 "2021-02-23T00:43:03Z")
Pretty much every time I’ve seen this the cause has been a tag somewhere addressing an address that is out of range or no longer exists in the PLC. When you try to subscribe the tags are getting put into the same request as this bad tag and it’s making the whole request fail. When you read in the QC it’s not combined with the bad subscribed item and it succeeds. ---
**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:** [February 23, 2021, 1:03am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/10 "2021-02-23T01:03:42Z")
> [@Kevin.Herron](#): > > and it’s making the whole request fail. An approach to finding the problem tag is to disable half of them. If the problem goes away, its in the group you disabled. Turn half of those back on to see if the problem returns. et cetera. (If the problem doesn't go away/doesn't return at any step, switch which half is disabled. Work from a tag export where you've searched for the device name to make sure you don't overlook any. ---
**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:** [February 23, 2021, 1:10am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/11 "2021-02-23T01:10:22Z")
Sounds like a binary search 🙂 ---
**Author:** ![calimero100582](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/calimero100582/32/18630_2.png) [@calimero100582](https://forum.inductiveautomation.com/u/calimero100582)\ **Post date:** [February 23, 2021, 2:18am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/12 "2021-02-23T02:18:51Z")
What addressing do you use as B3:35/3 always work for me so far, but B3:35.3 sometimes work ---
**Author:** ![nbrown](https://avatars.discourse-cdn.com/v4/letter/n/c6cbf5/32.png) [@nbrown](https://forum.inductiveautomation.com/u/nbrown)\ **Post date:** [February 23, 2021, 2:39am UTC](https://forum.inductiveautomation.com/t/opcua-server-quick-client-reads-but-cant-subscribe/43702/13 "2021-02-23T02:39:41Z")
Well, got on the horn with ignition support, no luck, nothing showing up in the logs either. They had never seen it… so… I created a second Binary group on my 1400, and that solved it. Maybe a driver issue. Who knows.