TimeoutException: Timeout expired while fetching topic metadata Kafka
org.apache.kafka.common.errors.TimeoutException: Timeout expired while fetching topic metadatacan happen when trying to connect to a broker expecting SSL connections and the client config did not specify;
security.protocol=SSL
One time I fixed this issue by restarting my machine but it happened again and I didn't want to restart my machine, so I fixed it with this property in the server.properties file
advertised.listeners=PLAINTEXT://localhost:9092
Kafka fetch topics metadata fails due to 2 reasons:
Reason 1 If the bootstrap server is not accepting your connections this can be due to some proxy issue like a VPN or some server level security groups.
Reason 2: Mismatch in security protocol where the expected can be SASL_SSL and the actual can be SSL. or the reverse or it can be PLAIN.