# Debugging Error 500 on Swagger Upload
# Overview
The purpose of this article is to provide additional support to users experiencing error code 500: "API Connection Error". For other error codes please see Common Failure Reason for Swagger Files Upload.
# Potential Causes
While an error code usually represents a general failure of the system to upload the Swagger specification, the most common reason is incorrect Swagger syntax as per the requirement of OpenAPI Specification 3.x and Swagger 2.x.
# How to Fix It?
To fix your Swagger syntax you may first want to understand how a Swagger document is structured. The Swagger documentation (opens new window) provides helpful resources to learn more.
Two types of syntax errors may exist in your Swagger file:
- Formatting errors. These are not specific to Swagger, but rather the YAML or JSON format that stores your Swagger specification. Double-check that all your brackets and quotes are paired up properly.
- Swagger validation errors. This has to do with what objects are allowed to be where in your document according to Swagger rules. A Swagger file may have valid JSON or YAML formatting but still violate Swagger rules.
Thankfully, both of these errors can be resolved by using a linter. A linter is a tool for highlighting errors in your text editor (usually VSCode). You can try some open-source tools such as the openapi-lint (opens new window) extension. Alternatively, you can import your Swagger file to the official Swagger web editor (opens new window), and it will display any errors you may have.
# Still getting this error code?
In the unlikely scenario that our services are under maintenance or are experiencing problems, you may receive this code even with a correct Swagger file. In this case, please send us an email at support@openapihub.com, and we will get back to you as soon as possible!
# Conclusion
Error 500 can be a scary error to receive, but don't worry! Double-check your Swagger file, and re-upload it again. If you still experience other error codes, refer to Common Failure Reason for Swagger Files Upload for more details!