Is this a conversion, or shop bought? Usually the former requires a complete reindex and stop limit adjustment. If it is shop bought, then take it back for a service. If you want to try yourself, then see below YouTube.
Usually with a crank motor, the chaingear wears relatively quickly and needs replacement of the chain, and cassette. With a rear hub motor, the chaingear lasts a long time.
Check that your rear derailleur is correctly indexed / adjusted. If it is slipping off into the gap between the smallest rear cog and the chainstays, you need the limit stops adjusted - If it isn't changing one gear at a time per single click of the shifter, it also needs reindexing.
Everything is fairly new ,half of me is thinking about going single speed .