It just may need slight adjustment to correct the problem, finding the problem takes a little patience..
Do not try this all at once do one step at a time...
Are you putting the presser foot down?
Are you using regular serger thread? Type of Fabric?
Make sure your machine is threaded properly go through each guide.
Are your needles inserted properly? Have you changed/checked the needles to make sure they are not bent or dull.
Check the width and lenghth of stitch
Could be tension settings. May need to tighten presser foot.
Could probably suggest 10 other things but enough for right now.
Althouh I do not have your machine have used many Brands of sergers and Models for about 49 years...........
Maybe bump up the differential a notch.

Thank you. I'll go through the list and try. I have done many of them but not all. I'm sure it's probably user error. The machine sews fine with only 3 threads. When I use the 4th thread and the fabric thickness changes (for instance when making an interlock fabric t-shirt and I sew on the waistband . . . when I cross over the seam in the band then the 4th thread starts skipping and sometimes breaks. I was using an old work horse kenmore that needed very little adjustment when going between fabric types or thickness . . . this machine seems very sensative!

Like sewing machines all sergers have some quirks.
The settings vary from each machine.
On adding the band, try increasing the pressure on the presser foot. Sometimes need to loosen the thread tension.
If thread breaking or skipping usually tension too tight.
If your sewing a lot of knits the needles and blades dull a little faster but since the machine is new the blades should be okay.
Try testing on scraps. In the back of most serger manuals they have a blank sheet when I get a correct setting for different fabrics or stitch types I record all the settings. Needle(s), Looper(s), Differential, Stitch Width and Lengths, it saves time in the future.
I have to admit on some fabrics I do actually do a basting stitch on the sewing machine.
Hope this is helping.