Maps Web Snapshots: 500 Internal Server Error

Currently (at least for a few days, maybe longer), when trying to create an Apple Maps Web Snapshot according to https://developer.apple.com/documentation/snapshots/generating_a_url_and_signature_to_create_a_maps_web_snapshot with a custom image marker (passed as Base64 PNG), the Apple server responds with a 500 Internal Server Error. Using the default balloon marker works, but a custom Base64 image marker used to work in the past (and still should according to the documentation).

Maps Web Snapshots: 500 Internal Server Error
 
 
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