Ollama API: 403 Forbidden sur POST /api/chat (CORS moz-extension://) avec Ollama 0.18.2

[viba1]

The problem

ThunderAI no longer works with local Ollama: 403 Forbidden error on POST /api/chat from Thunderbird extension. GET /api/tags succeeds (200 OK), but chats fail.

Ollama Logs (journalctl -u ollama)

ollama: [GIN] 2026/03/26 - 12:34:49 | 200 | 3.565982ms | 127.0.0.1 | GET "/api/tags"
PC ollama: [GIN] 2026/03/26 - 12:34:56 | 403 | 3.076µs | 127.0.0.1 | POST "/api/chat"

• OS: Debian 13
• Thunderbird: 140.9-esr
• ThunderAI: 4.0.2
• Ollama: 0.18.2
• Models tested: gemma3, gpt-oss

Ollama settings:
OLLAMA_HOST=1.1.1.1 or OLLAMA_HOST=0.0.0.0 leads to the same error
OLLAMA_ORIGINS=moz-extension://* or OLLAMA_ORIGINS=* leads to the same error
disabling the firewall leads to the same error

Do you have any idea? Or a test I can do?

Which Operative System are you using?

Debian 13

Which version of Thunderbird are you using?

140.9-esr

Which version of ThunderAI has the issue?

4.0.2

Which integration are you using?

Ollama API

Anything in the Thunderbird console logs that might be useful?

[ThunderAI Logger | mzta-background] Executing shortcut, promptId: prompt_reply mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] [startWorking] WorkingLevel: 1 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] [stopWorking] WorkingLevel: 0 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] Prompt length: 529 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] Ollama API window opening... mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] Applying saved window dimensions: width=700, height=800 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] Ollama API window ready. mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] message.window_id: 236 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] createdTab3.id: 27 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] mailMessageId3: 1 mzta-logger.js:35:44
[ThunderAI Logger | mzta-background] [Ollama API] Connection succeded! mzta-logger.js:35:44
[ThunderAI Logger | model-worker-ollama] error_message: "Forbidden" mzta-logger.js:35:44
Error: [ThunderAI] Ollama API request failed: 403 Forbidden, Detail: Forbidden

Additional information

No response

[evolts21]

The reason GET /api/tags still works is that Ollama applies the CORS origin check differently for requests with a body (POST) vs. simple GET requests, so the tag list fetch passes, but the actual chat call gets blocked.

May you try this fix?

sudo systemctl edit ollama

Add the following lines in the editor that opens:

[Service]
Environment="OLLAMA_ORIGINS=moz-extension://*"
Environment="OLLAMA_HOST=0.0.0.0"

Then reload and restart the service:

sudo systemctl daemon-reload
sudo systemctl restart ollama

You can verify the variables are actually loaded by the service with:

sudo systemctl show ollama --property=Environment

Also, be aware that OLLAMA_HOST=1.1.1.1 is the Cloudflare public DNS IP and is definitely not a valid local interface address. Please make sure to use 0.0.0.0 (to listen on all interfaces) or 127.0.0.1 (localhost only) instead.
Let me know if this solves it!
Thank you!

[github-actions]

There hasn't been any activity on this issue in the past 7 days. It will be closed in 3 days if no further activity occurs.

[viba1]

Hi,
Thanks for your help.
It was an environmental problem. It's working now.

[micz]

Great, thank you for your feedback.
I'm closing this issue now, feel free to open it again if needed.