Unexpected token 'e', "error code: 526" is not valid JSON

SyntaxError: Unexpected token 'e', "error code: 526" is not valid JSON
    at async Object.<anonymous> (functionsWorker-0.23271184708511838.js:2691:18)
    at async resourceFetcher (functionsWorker-0.23271184708511838.js:2529:22)