# Troubleshooting Guide

Facing issues while using the OpenAI Kotlin API Client? Here are some common problems and their solutions.

<details>
  <summary>I'm seeing "The model: gpt-4 does not exist"</summary>

The access to GPT-4 API is restricted at the moment. You can join the waitlist using [this form](https://openai.com/waitlist/gpt-4-api).
</details>