ValueError: Invalid EC key at get_locations

[coolcodecding]

I have generated keys and flashed an ESP32 (which seemed to work well). At first i had no results:
{'results': [], 'statusCode': '200'}

and after a few minutes i got
{'results': [{'datePublished': 1724241076293, 'payload': 'LHYLBwADBGPB5h4yDMucxvuBtwNoaN5qwNSeI9xIwcry75DigWvtGTx5++pe4NV+VODBThT5FggjCV0JWUlVpXIVCwqgT7s4HSub1bVZX2qSDebcmtF/I3Q=', 'description': 'found', 'id': 'nma57Na8s2yC/ECzoGYjZWC0dTAY4+JFftV0xbLBB9o=', 'statusCode': 0}], 'statusCode': '200'}

but decryption fails:
eph_key = ec.EllipticCurvePublicKey.from_encoded_point(ec.SECP224R1(), data[5:62])
ValueError: Invalid EC key.

What could be the reason?