Fixing the “Model Not Found / Regeneration Must Have Conversation ID” Error in ChatGPT

Recently, many ChatGPT users have reported running into a frustrating problem:. The issue is seen with all different devices like android, iphone , PC and MacBook. The error faced are :

“Model not found.”
“Regeneration must have conversation_id.”

Fixing the “Model Not Found / Regeneration Must Have Conversation ID” Error in ChatGPT

This error typically appears when trying to reopen older chats, work on ongoing projects, or even when attempting to regenerate a response.

What Causes the Error- chatgpt “Model not found”?

From user reports and OpenAI support responses, here are the common causes:

Old Conversations
- Older chats may be linked to models or IDs that are no longer supported. Trying to regenerate or modify code in those chats triggers errors.
Custom GPTs Bug
- Custom GPTs (especially newly created ones) were affected by a bug where they could not be loaded properly, resulting in “Model not found.”
App-Specific Issues
- Android app users reported the error more often. Interestingly, logging into ChatGPT via a web browser worked fine, while the mobile app showed the bug.

Common Fixes That Helped Users

Logout and Login Again: Sometimes clears corrupted session data.
Clear Cache: Both browser and app cache clearing has worked for some.
Reinstall the App: A fresh install may restore functionality temporarily.
Disable Developer Mode: Some users found turning this off fixed the issue.
Try Web Browser Instead of App: Many confirmed chats and projects continued to work in a browser even when the app failed.

Official Update from OpenAI

According to Dax from OpenAI Support:

“We are aware of an issue with custom GPTs whereby ‘Model not found’ errors are occurring when trying to create/chat with a custom GPT. Our engineering team is working on a fix.”

Later, OpenAI confirmed:

“We pushed changes to fix this error last night! Let me know if anyone is still affected and we’ll be happy to help.”

Bottom Line

If you’re still seeing the “Model not found” error:

First, try logging out, clearing cache, or switching to web chat.
If it persists, it’s most likely a temporary server-side issue.
Keep an eye on official OpenAI status updates for fixes.

This bug highlights the importance of backing up important code, macros, or project outputs outside of the chat environment — so you’re not locked out when technical issues arise.