HCL Sametime 11.6 is supporting MongoDB 4.4 and this is the suggested version in case of new install.
One of the suggested steps during a Community setup is enable the Mongo security as described here , but the steps there are not enough, because 4.4 version in case of replica set , require also the creation and the use of a shared key to every Mongo server involved in the replica set, even if the replica set is composed by 1 node.
This is a companion discussion topic for the original entry at https://blog.msbiro.net/2021/06/hcl-sametime-116-mongodb-44-enable-security-mongo-key-replica-set.html