Why does OpenAI return an API key error?

OpenAI API key errors usually mean the key is missing, copied incorrectly, revoked, or not connected to an account with access and billing configured.

Why does MLJAR Studio show Ollama connection refused?

Ollama connection refused usually means the Ollama server is not running, the endpoint URL is wrong, or another process/network rule is blocking the local port.

Why is my local Ollama model slow?

Local model speed depends on model size, CPU, RAM, GPU availability, and context length. Try a smaller model if your machine is slow.

What should I check first when an LLM provider fails?

Check the provider type, API key if required, endpoint if required, model name, network access, and whether Test connection succeeds before trying to save the provider.

LLM Providers

LLM Setup Troubleshooting

This page lists common setup problems for OpenAI, Ollama local models, and Ollama-compatible remote endpoints in MLJAR Studio.

Provider cannot be saved

You need to click Test connection before saving a provider. MLJAR Studio tests whether the provider can be reached and whether the selected model is available. The Save provider button becomes active only after the test succeeds.

After you click Save provider, you should see a success toast. The active provider then appears in the top chip in the sidebar with a green dot.

OpenAI API key error

If OpenAI authentication fails, check the following:

The API key was copied completely.
The API key was not revoked in the OpenAI dashboard.
The OpenAI account has billing enabled if required.
The selected model is available to your account.
There are no extra spaces before or after the key.

OpenAI invalid model error

An invalid model error usually means the model name is wrong or your account does not have access to that model. For example, you can test with gpt-5.4 if it is available in your account. Try a model name you know is enabled, then click Test connection again.

Ollama connection refused

This usually means MLJAR Studio cannot reach the Ollama server. Check that Ollama is installed and running.

ollama --version
ollama list

Also check that the endpoint is correct. The default local endpoint is usually:

http://localhost:11434

Ollama model not found

If the model is missing, download it first. The model name in MLJAR Studio should match the model available in Ollama.

ollama pull qwen-3.5:27b
ollama pull gemma4:31b
ollama list

Local model is too slow

Local inference speed depends on your hardware and model size. If the model is too slow, try a smaller model, close other heavy applications, or use a remote provider such as OpenAI or an Ollama-compatible cloud endpoint.

Ollama Cloud does not connect

Check that the Ollama API key is correct.
Check that the model name is correct, for example qwen3.5:397b or gemma4:31b.
Confirm that the model is available in your Ollama Cloud account.
Click Test connection again before saving the provider.
Ask your IT or infrastructure team whether a proxy, firewall, or VPN rule is blocking access.

Still not working?

Review the provider setup pages again: OpenAI Integration, Ollama Local Setup, and Ollama Cloud Setup.