Apache Spark Streaming from Azure Event Hubs with Databricks Error: Endpoint hostname cannot be null or empty - spark-streaming

Question

I am successfully streaming data to Azure Event Hub, howevever when I attempt to write the the stream using the code below, I get the following error:
Endpoint hostname cannot be null or empty
=== Streaming Query ===
Identifier: [id = 5b2fef8d-886a-411f-b39e-7b2540361cea, runId = 43b637e5-e1ca-47d0-b64e-b4a7af4c84e6]
Current Committed Offsets: {}
Current Available Offsets: {}
Current State: INITIALIZING
Thread State: RUNNABLE
logged message The streaming query failed to execute
Exception: Endpoint hostname cannot be null or empty
=== Streaming Query ===
Identifier: [id = 5b2fef8d-886a-411f-b39e-7b2540361cea, runId = 43b637e5-e1ca-47d0-b64e-b4a7af4c84e6]
Current Committed Offsets: {}
Current Available Offsets: {}
Current State: INITIALIZING
Thread State: RUNNABLE
The code that I'm using to write the streams is as follows:
streamingQuery = (
df
.writeStream
.format("delta")
.outputMode("append")
.option("checkpointLocation", f"{thelocation}/_checkpoints")
.start(thelocation)
)
Any thoughts on resolving the issue?
I am passing Endpoint details as follows:
df_flight_data = flightdata_defn.build(withStreaming=True, options={'rowsPerSecond': 1})
streamingDelays = (
df_flight_data
.groupBy(
#df_flight_data.body,
df_flight_data.flightNumber,
df_flight_data.airline,
df_flight_data.original_departure,
df_flight_data.delay_minutes,
df_flight_data.delayed_departure,
df_flight_data.reason,
window(df_flight_data.original_departure, "1 hour")
)
.count()
)
writeConnectionString = sc._jvm.org.apache.spark.eventhubs.EventHubsUtils.encrypt(connectionString)
checkpointLocation = "///checkpoint"
# ehWriteConf['eventhubs.connectionString'] = sc._jvm.org.apache.spark.eventhubs.EventHubsUtils.encrypt(connectionString)
# ehWriteConf = {
# 'eventhubs.connectionString' : writeConnectionString
# }
ehWriteConf = {
'eventhubs.connectionString' : writeConnectionString
}
# Write body data from a DataFrame to EventHubs. Events are distributed across partitions using round-robin model.
ds = streamingDelays \
.select(F.to_json(F.struct("*")).alias("body")) \
.writeStream.format("eventhubs") \
.options(**ehWriteConf) \
.outputMode("complete") \
.option("checkpointLocation", "...") \
.start()