🧠 What Is This Error?
When you send a custom prompt to Atlas Brain and receive a persistent 400 error, this is almost always caused by a missing OTTO SEO project for your domain. Atlas Brain requires an active OTTO SEO project to process tool calls and generate responses. Without one, every request fails at the API level before Atlas Brain can do any work.
This is not a system-wide outage. It affects only domains that have not yet been connected to an OTTO SEO project.
⚠️ Why Does This Happen?
Atlas Brain uses your OTTO SEO project as its source of context — it pulls your domain data, crawl results, and SEO settings to power its responses. If no active project exists for the domain you are working with, Atlas Brain has no context to reference and returns a 400 Bad Request error instead of a response.
Common situations where this occurs include:
- You are using Atlas Brain for the first time on a domain that has never had an OTTO SEO project created.
- A previous OTTO SEO project was deleted or disconnected from the domain.
- You are testing Atlas Brain on a new domain you recently added to your account.
✅ How to Fix It: Create an OTTO SEO Project
The resolution confirmed by our support team is to create an OTTO SEO project for your domain. To do this, navigate to the OTTO SEO section of the platform and create a new project for the domain you are working with. Once the project has been created and is set up for your domain, return to Atlas Brain and re-send your custom prompt. The 400 error should no longer occur.
🔍 How to Confirm the Error Is Resolved
After creating the OTTO SEO project, return to Atlas Brain, select the same domain, and send a prompt. If Atlas Brain returns a response instead of a 400 error, the issue is resolved. If you still see a 400 error, confirm that the OTTO SEO project has been created for the correct domain.
If you need further assistance, open the chat widget in the bottom-right corner of the platform and type human teammate to be connected with a member of our team.