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Troubleshooting MCP

When sign-in, connection, or a tool run fails on the Files.com MCP Server, the error message identifies the cause. For client-specific behavior, also refer to the documentation for the MCP clientExternal LinkThis link leads to an external website and will open in a new tab you are using with the Files.com MCP Server.

Couldn't Complete OAuth Redirect

When Sign In with Files.com fails, the browser displays an error page titled Couldn't Complete OAuth Redirect with the message Your site does not allow this client to register for MCP access. Please contact your site administrator.

The error appears after you log in. It means that your Files.com site accepted your login and then refused to register the MCP client that requested access. Two settings can cause the refusal.

If your MCP client requires Dynamic Client Registration (DCR), then a Site Administrator must enable the MCP Dynamic Client Registration setting, which is disabled by default.

If all AI features are disabled for your site, then the Remote MCP Server is unavailable and no client can register. A Site Administrator can enable AI features for the site.

Authentication Error When Running Tools

Tool runs can fail with the error Authentication Error: HTTP 401 The API key or Session token provided could not be used to validate this request. even though your MCP client connected successfully.

This error means that your Files.com site rejected the API key or the Sign In with Files.com session that your MCP client presented. The Files.com MCP Server checks your credential only when a tool runs, so connecting and listing tools succeed even when the credential is not valid.

If you authenticate with an API key, generate a new Files.com API Key and update the key in your MCP client configuration file. If you authenticate with Sign In with Files.com, sign in again from your MCP client.

Could Not Connect to MCP Server

The Could not connect to MCP server Files.com error indicates that your MCP client could not start or reach the Files.com MCP Server. Check your MCP client's logs for the underlying error, which is usually one of the startup errors below.

Cannot Find the uvx Command

The spawn uvx ENOENT error indicates that the uvx command cannot be found on the system PATH environment variable.

Install uvExternal LinkThis link leads to an external website and will open in a new tab on your system.

If the uvx command is not installed in a system PATH location, then update the MCP client JSON configuration file to specify the full path to the uvx command.

For example, in the configuration file, change:

  "command": "uvx",

to:

  "command": "C:\path\to\local\bin\uvx",

You can find the location of the uvx command using the following commands from a terminal window:

On Windows, run where uvx. On Mac, run which uvx.

Cannot Find the npx Command

The spawn npx ENOENT error indicates that the npx command cannot be found on the system PATH. npx is included with Node.js. Install Node.jsExternal LinkThis link leads to an external website and will open in a new tab on your system.

If npx is installed but not in a system PATH location, update the configuration file to specify the full path to the npx command.

For example, change:

  "command": "npx",

to:

  "command": "C:\path\to\local\bin\npx",

You can find the location of the npx command using the following commands from a terminal window:

On Windows, run where npx. On Mac, run which npx.