@DNT - The error message you are seeing indicates that there is a null reference found during serialization due to variable schema. This error can occur when the schema of the data being serialized is not properly defined or is not being passed correctly.
To resolve this issue, you can try the following steps:
Check the schema of the data being serialized and ensure that it is properly defined. You can refer to the documentation for more information on defining schemas for data in Azure Event Hubs.
Ensure that the schema is being passed correctly to the serialization process. You can check the code for any issues related to passing the schema.
If the issue persists, you can try using a different serialization format such as JSON or CSV to see if the issue is specific to the Parquet format.
If none of these steps resolve the issue, please provide more information about the code and configuration you are using so that I can assist you better.