Client will not connect

We have a situation where some of our Broker Clients will not connect after a restart. They were connected before the restart. Out of 64 Clients four did not connect after the restart. All four are MQ Clients yet some of the MQ Clients did connect. In one case two MQ triggers are in the same package… one connected and one didn’t. This is not the first time we have had issues with Clients not connecting. Recently a new Client was deployed (not an MQ trigger) and would not connect on the targer server. We had to manually edit the trigger on both servers as close to simultaneously as possible using Developer, disable it, save, enable, save and then it connected. Any suggestions/ideas? Any help is greatly appreciated. The queues are backing up and we need the messages. We can’t clear them.