MCP, API and webhooks
When a connection or a tool fails
What the common MCP errors mean and what to do about each one.
The connection itself
| What you see | What it means | What to do |
|---|---|---|
| The client asks you to sign in again | The credential is missing, revoked or expired | Re authorise. Repeating the same request won't help. |
| Everything is refused after a while | The MCP session expired | Reconnect, then pick the brand again. |
| Requests start failing in bursts | Rate limited for this credential | Wait the time the error names, then try the same thing again. |
Refusals before anything ran
Nothing changed when you see these.
| Message names | Meaning | What to do |
|---|---|---|
| Access or scope | The connection doesn't carry the access the tool needs | Grant it in API & Webhooks, or use a connection that has it. |
| This key isn't turned on for MCP | The API key was created for the REST API only | An owner or admin turns on MCP for the key, or creates one with it on. |
| This brand isn't allowed | The API key is limited to other brands | Pick one of the key's brands, or use a key that covers this one. |
| No brand is active | Nothing brand specific can run yet | Ask the assistant to list your brands and pick one. |
| Your plan | Your Koast plan doesn't include that tool, or MCP itself. MCP needs a paid plan with an active subscription | Change plan, or do it in the app. |
| This ad account | The brand's ad provider doesn't support it | A brand on a different provider may. |
| Publish limit | There's no publish limit and Unlimited is off, or the launch would exceed the limit | Set or raise the limit, or turn on Unlimited on an API key. Nothing was published. |
| Confirmation | The client couldn't ask you to confirm, or you declined | Nothing was published. Try from a client that can prompt. |
Refusals from the tool
| Message names | Meaning | What to do |
|---|---|---|
| Not found | The id doesn't exist under this brand or batch | Ask the assistant to re list and try again. |
| Permission or role | Your role doesn't carry it | An organization admin has to grant it. |
| Changed since you read it | Something moved underneath | Re read and retry. |
| More than one ad account | The request was ambiguous | Name the account. |
| Read only right now | The surface can't write | Switch out of a read only mode or connection. |
One retry, then stop
If a refusal is about access, plan or provider support, it will fail the same way every time. Retrying burns your rate limit and tells you nothing new.
Nothing here matches
Contact Koast support with the message the assistant showed you, word for word, and roughly when it happened.