Appsmith server not booting in latest upgrade v1.6.4

My Appsmith instance just upgraded to v1.6.4 and it’s not booting up anymore. In the logs, I can see the exception below:

Caused by: com.mongodb.MongoCommandException: Command failed with error 17 (ProtocolError): 'Attempt to switch database target during SASL authentication.' on server mongo:27017. The full response is {"ok": 0.0, "errmsg": "Attempt to switch database target during SASL authentication.", "code": 17, "codeName": "ProtocolError"}

Is there anything I can do to bring up my Appsmith instance?

In release v1.6.4 , we upgraded our libraries & Spring framework. This caused a compatibility issue between the libraries used within Appsmith and the version of MongoDB that was shipped earlier. This didn’t show up in our testing because all our testing happened against MongoDB clusters with replica sets, where the problem doesn’t surface. We apologize for this breaking experience.

A step-by-step guide to fix this issue is described here.