Rejected Promise in the server process

[ChristophNiehoff]

When running the server there is a periodically appearing rejected Promise:

(node:8) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:8) UnhandledPromiseRejectionWarning: Error: EISDIR: illegal operation on a directory, read