Messages do not show

I have two servers setup (A and B) they are interconnected in Openfire, however when using Spark 2.6.3 sometimes the messages don’t show up.

When a user on A sends a messsage to a user on B, Spark on B pops up with a new message but there is nothing there, if you close the window and reopen the person who sent the message, the message sent shows up in the history. When user B responds back, it doesn’t show anything on user B’s screen, but the message shows up at user A. Is there something misconfigured or ? Openfire is same version on both servers, so is Spark.

This might be related to the fact that Spark was installed in a mode without admin rights. Do the users see the emoticons in the chat window (that would be smileys and such)? What is in the Spark error log?