You need to know whether the panel is having problems or something in the rest of the building is having problems. Start by dividing the panel from the building fire alarm system.
Disconnect all wires from the panel; see if the panel becomes stable. If, with all wires disconnected, the problems persist, the panel may have problems and needs repair or replacement. If the problem stops, start connecting the wires, one pair at a time. Find what wires cause the problem and continue to troubleshoot from there. When doing this, take pictures before doing anything, and carefully mark all wires so they can be landed on the same terminal they came from originally.
Watch out for "false fixes". These are "fixes" where the panel quits having problems when the technician is in site, but sometime after the technician leaves, the troubles come back. It could be a thermal problem inside the panel that only shows up after the door has been closed for a while. The problem is that when the door is opened to service the panel, the panel cools down just a few degrees. That few degrees cooler is enough to make the panel stable. When the door to the panel is closed because the technician is leaving, it takes a little while to heat up a few degrees in the panel, and then the troubles come back.
I've seen this kind of trouble only once every 5 years or so, but this actually does happen. Usually the panel needs replacement.
Just use standard troubleshooting procedures; assume the problem is somewhere, and do what it takes to find it and then fix it.