AI Assistant Codex error "Failed to initialize ACP session. Error: Internal error"

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I had the same error: Failed to initialize ACP session. Error: Internal error: "no rollout found for thread id <thread number>"… Basically cannot continue developing in the thread. It happened after I upgraded PyCharm. Filed a support ticket, with upload ID

I reinstalled pycharm and fixed the error.

same issue here on pycharm when trying to use gpt 5.4 on a 5.3-codex session. I created a new session and everything is working

It occurred again today. Again, after I updated AI Assistant plug-in. But it hung even with a new chat. I had to uninstall Codex and reinstall it. Painful

I have the same issue

Have the same issue

Hi there,

Please submit a request via YouTrack to tell us about the issue in detail:
https://youtrack.jetbrains.com/issues/LLM

Or contact the support team at https://jb.gg/ai-assistant-support so we can assist you directly.

I meet this because my team plan is outdated.

I check ACP logs and find cursor agent command location in ~/.cache/JetBrains/GoLand2026.1/acp-agents/cursor/2026.07.09/dist-package/cursor-agent, do logout and signin by it.

Have the same issue! :-(

2026-07-21 14:54:44,684 [11734905]   INFO - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - [Junie] Creating new session for chat f7088097-c64b-4931-a3cf-b4532d70825b
2026-07-21 14:54:44,684 [11734905]   INFO - #c.i.m.l.a.a.c.ClientInfoMetaService - Resolved 4 proxy servers: [openai, anthropic, google, bedrock]
2026-07-21 14:54:44,684 [11734905]   INFO - #c.i.m.l.a.a.c.ClientInfoMetaService - Built ClientMeta with 4 proxies after license filtering
2026-07-21 14:54:46,299 [11736520]   INFO - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - Initializing ACP client session with capabilities: ClientCapabilities(fs=FileSystemCapability(readTextFile=true, writeTextFile=true, _meta=null), terminal=false, auth=AuthCapabilities(_meta={"gateway":true}), nes=null, positionEncodings=null, elicitation=null, _meta={"terminal-auth":true}), meta: true, response: com.agentclientprotocol.agent.AgentInfo@e9ff2a9
2026-07-21 14:54:46,301 [11736522]   INFO - #c.i.m.l.a.a.c.RequiredPluginsManager - Agent requires plugin: org.jetbrains.junie (comment: Required for IDE integration, channel: stable)
2026-07-21 14:54:46,301 [11736522]   INFO - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - Required plugins check passed
2026-07-21 14:54:46,301 [11736522]  FINER - #c.i.m.l.a.a.c.AcpLocalSessionLifecycleManager - Exposing configured MCP servers for agent acp.registry.junie: 
2026-07-21 14:54:46,301 [11736522]   INFO - #c.i.m.l.a.a.c.a.AcpAuthenticationService - acp.registry.junie: get auth EXPLICIT_SELECTION
2026-07-21 14:55:43,552 [11793773]   INFO - #c.i.m.l.a.a.c.a.AcpAuthenticationService - acp.registry.junie: set auth JETBRAINS_AI
2026-07-21 14:55:43,679 [11793900]   INFO - #c.i.m.l.a.a.c.a.AcpAuthenticationService - Successfully initialized authenticated gateway for LlmApiOpenAI at http://127.0.0.1:50000
2026-07-21 14:55:43,689 [11793910]   INFO - #c.i.m.l.a.a.p.AcpProcessHandlerService - Stopping process handler for agent acp.registry.junie in chat f7088097-c64b-4931-a3cf-b4532d70825b
2026-07-21 14:55:43,689 [11793910]   INFO - #c.i.m.l.a.a.p.AcpServerProcessHandlerImpl - [Junie] Stopping server
2026-07-21 14:55:43,689 [11793910]   INFO - #c.i.m.l.a.a.p.AcpProcessHandlerService - Successfully stopped process handler for agent acp.registry.junie in chat f7088097-c64b-4931-a3cf-b4532d70825b
2026-07-21 14:55:43,689 [11793910]   WARN - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - Failed to initialize ACP session for chat f7088097-c64b-4931-a3cf-b4532d70825b, error: com.agentclientprotocol.protocol.JsonRpcException: Session is not loaded: session-260721-145433-1q5z
com.agentclientprotocol.protocol.JsonRpcException: Session is not loaded: session-260721-145433-1q5z
    at com.agentclientprotocol.protocol.Protocol.handleResponse(Protocol.kt:485)
    at com.agentclientprotocol.protocol.Protocol.handleIncomingMessage(Protocol.kt:385)
    at com.agentclientprotocol.protocol.Protocol.access$handleIncomingMessage(Protocol.kt:129)
    at com.agentclientprotocol.protocol.Protocol$start$2.invokeSuspend(Protocol.kt:180)
    at kotlin.coroutines.jvm.internal.BaseContinuationImpl.resumeWith(ContinuationImpl.kt:34)
    at kotlinx.coroutines.DispatchedTask.run(DispatchedTask.kt:100)
    at kotlinx.coroutines.scheduling.CoroutineScheduler.runSafely(CoroutineScheduler.kt:610)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runDefaultDispatcherTask(CoroutineScheduler.kt:1194)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.executeTask(CoroutineScheduler.kt:906)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.runWorker(CoroutineScheduler.kt:775)
    at kotlinx.coroutines.scheduling.CoroutineScheduler$Worker.run(CoroutineScheduler.kt:762)
2026-07-21 14:55:43,690 [11793911]   INFO - #c.i.m.l.a.a.p.AcpServerProcessHandlerImpl - [Junie] Killing process tree 25448...
2026-07-21 14:55:43,690 [11793911]   FINE - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - handleSessionConnectionFailed for agent=acp.registry.junie, chatId=f7088097-c64b-4931-a3cf-b4532d70825b, recoverable=false, cause=null, message=Failed to initialize ACP session. Error: Session is not loaded: session-260721-145433-1q5z, reconnectState=idle, hasStoredSessionId=true, hasLiveSession=false
2026-07-21 14:55:43,690 [11793911]   FINE - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - Stopping ACP reconnect loop for agent=acp.registry.junie, chatId=f7088097-c64b-4931-a3cf-b4532d70825b, reason=received non-recoverable session failure, loopActive=false
2026-07-21 14:55:43,690 [11793911]   INFO - #c.i.m.l.a.a.c.a.AcpAuthenticationService - acp.registry.junie: get auth JETBRAINS_AI
2026-07-21 14:55:43,876 [11794097]   INFO - #c.i.m.l.a.a.p.AcpServerProcessHandlerImpl - [Junie] Process stopped after termination request (exit code 1)
2026-07-21 14:55:43,876 [11794097]   INFO - #c.i.m.l.a.a.p.AcpServerProcessHandlerImpl - [Junie] Cleaning up process resources
2026-07-21 14:55:43,876 [11794097]   INFO - #c.i.m.l.a.a.p.AcpServerProcessHandlerImpl - [Junie] Cleaning up process resources
2026-07-21 14:58:28,283 [11958504]   INFO - #c.i.m.l.a.a.c.a.AcpAuthenticationService - acp.registry.junie: set auth EXPLICIT_SELECTION
2026-07-21 14:58:28,283 [11958504]   INFO - #c.i.m.l.a.a.c.a.AcpAuthenticationService - acp.registry.junie: set auth EXPLICIT_SELECTION
2026-07-21 14:58:28,283 [11958504]   FINE - #c.i.m.l.a.a.p.AcpProcessHandlerService - No process handler found for agent acp.registry.junie in chat f34dd584-2086-4c26-8376-1e14b5df5f52
2026-07-21 14:58:28,284 [11958505]   FINE - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - handleSessionConnectionFailed for agent=acp.registry.junie, chatId=f34dd584-2086-4c26-8376-1e14b5df5f52, recoverable=false, cause=null, message=Authentication Required, reconnectState=disposed, hasStoredSessionId=true, hasLiveSession=false
2026-07-21 14:58:28,284 [11958505]   FINE - #c.i.m.l.a.a.c.AcpSessionLifecycleManager - Ignoring ACP session failure because lifecycle manager is already disposed for agent=acp.registry.junie, chatId=f34dd584-2086-4c26-8376-1e14b5df5f52