Secrets retriever fails often

I use the Secrets retriever to protect the bearer token needed to access our Web Application. As we retention this token after 3 minutes, I get the secret in front of each Web access. As now, this access just doesn’t work and the node comes back with “Execution failed: unable to fetch Secret 1: Unable to fetch token, endpoint returned internal server error, try again later (Status 503)”. Anyone an idea how make this access more stable?