When attempting to connect to a mongodb replicaset, if a password contains a "%", the following error will appear in kafka connect hub: Invalid value [URI] for configuration connection.uri: URLDecoder: Illegal hex characters in escape (%) pattern - Error at index 0 in: [string after %]. 

URI structure:

mongodb://user@password@host:port,user@password@host:port,user@password@host:port

There are no options to connect to the cluster with a username and password so it cannot be used as a workaround. We are forced to use the URI as shown in the options.png screenshot.

Connector version:
mongodb/kafka-connect-mongodb:1.8.1