Copying data from KSQLDB to SQLServer

We have created a kafka Stream in KSQLDB joining 2 streams.
It is in AVRO format.
The default Topic that gets created is used to sync data to Sqlserver using Kafka sink connector.
I am able to see data in the kafka topic with the print command in ksqldb.

However, the sink connector fails with : Error retrieving Avro key schema for id 0\nCaused by: Schema 0 not found