topic Re: ASCR callback channel error popup in Product Forum

ASCR callback channel error popup

Jesada — Mon, 10 Feb 2025 20:34:07 GMT

Hello,

I have 2 Blue Prism environments - one is running server 2016 and the other is running server 2022.

The ASCR configuration is the same between the two environments.

On the server 2022 environment, we are receiving the callback channel error popup whenever we try to start processes in the control room or with taking any actions in the control room.

Here is an excerpt from the logs located C:\ProgramData\Blue Prism Limited\Blue Prism\Logs

Grpc.Core.RpcException: Status(StatusCode="Unavailable", Detail="failed to connect to all addresses", DebugException="Grpc.Core.Internal.CoreErrorDetailException: {"created":"@1739212675.211000000","description":"Failed to pick subchannel","file":"..\..\..\src\core\ext\filters\client_channel\client_channel.cc","file_line":3009,"referenced_errors":[{"created":"@1739212652.766000000","description":"failed to connect to all addresses","file":"..\..\..\src\core\ext\filters\client_channel\lb_policy\pick_first\pick_first.cc","file_line":398,"grpc_status":14}]}")
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at BluePrism.ClientServerResources.Grpc.RegisterClientCallback.<HandshakeAsync>d__38.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at BluePrism.ClientServerResources.Grpc.InstructionalClientGrpcController.<<RegisterClient>b__64_0>d.MoveNext()
2025-02-10 12:37:58.2432-06:00 <servername> INFO BluePrism.ClientServerResources.Grpc.InstructionalClientGrpcController processid=5876 thd=27 1699332146080 ..\..\..\src\core\ext\filters\client_channel\subchannel.cc:980: Failed to connect to channel, retrying
2025-02-10 12:37:58.2432-06:00 <servername> INFO BluePrism.ClientServerResources.Grpc.InstructionalClientGrpcController processid=5876 thd=grpc 3 (cq 3) 0 ..\..\..\src\core\ext\filters\client_channel\http_connect_handshaker.cc:332: Connecting to server <servername>:10000 via HTTP proxy ipv4:xxx.xxx.212.93:80
2025-02-10 12:37:58.2588-06:00 <servername> INFO BluePrism.ClientServerResources.Grpc.InstructionalClientGrpcController processid=5876 thd=grpc 3 (cq 3) 0 ..\..\..\src\core\ext\filters\client_channel\subchannel.cc:1012: Connect failed: {"created":"@1739212678.262000000","description":"HTTP proxy returned response code 502","file":"..\..\..\src\core\ext\filters\client_channel\http_connect_handshaker.cc","file_line":252}
2025-02-10 12:37:58.2588-06:00 <servername> INFO BluePrism.ClientServerResources.Grpc.InstructionalClientGrpcController processid=5876 thd=grpc 3 (cq 3) 0 ..\..\..\src\core\ext\filters\client_channel\subchannel.cc:957: Subchannel 0000018BA598A500: Retry in 42855 milliseconds

Re: ASCR callback channel error popup

harish.mogulluri — Tue, 11 Feb 2025 23:55:52 GMT

Hi @Jesada

Check below BP Knowledge base article.

https://support.blueprism.com/en/support/solutions/articles/7000076986-bpe-error-unable-to-establish-communication-with-server-callback-channel-when-trying-to-run-a-proc

Thanks,

Harish

Re: ASCR callback channel error popup

Jesada — Wed, 12 Feb 2025 20:51:35 GMT

Hello Harish,

Thank you for the suggestion. I have followed all the steps provided in that support article including extending the resource connection timeout. I have a ticket open with support and waiting to hear next steps.

Re: ASCR callback channel error popup

DevendranVenkatesh — Thu, 13 Feb 2025 11:49:53 GMT

Hi @Jesada

I'm using 7.1.2 blueprism version with SQL 2019. After started using this version for initial few weeks I was facing same issue.

I performed below steps and the issue resolved for me.

1)BP App server 1st page, where it's asking hostname or IP. There I kept the hostname of the app server (the same name should be applied in SPN as well).
2)ACSR setting page, I selected 'gPRC' and kept same hostname whatever I kept in first page of the BP App server.
3)Updated port number as '10000' and the same should be enabled in firewall level as well for both app server and RR machines.
4)Connection mode selected as 'Insecure'

Re: ASCR callback channel error popup

AkshayaRamesh11 — Thu, 08 May 2025 08:24:21 GMT

Hi @DevendranVenkatesh

Good day!

I have the settings as you have mentioned. But I am still unable to connect the interactive client to the application server.

What else could have went wrong?

And we we have to provide this port 10000 in callback port field in connection configuration window of IC or will it remain 0?

Thanks,

Akshaya

Re: ASCR callback channel error popup

DevendranVenkatesh — Wed, 08 Oct 2025 12:50:17 GMT

Can you please share your BP app server configuration if possible?

Re: ASCR callback channel error popup

DevendranVenkatesh — Wed, 08 Oct 2025 13:45:46 GMT

1. Is your current environment a new setup, or was it working previously?

2. What connection method is configured in your connection string?

3. Has an SPN been created for your BluePrism application server?