Unable to decode the e2ee_private_key file '%1'. The error code is %2

Error code 257
Error constant E2EE_DECODING_PRIVATE_KEY_FILE
Parameter 1 The private key file from the e2ee_private_key option.
Parameter 2 The error code.
Probable cause

The file was found and its contents were read, but there was an error decoding the file. Please contact technical support and provide the error code.