Update firmware for your printer and software that you are using

Make sure the .gx file was sliced for your printer model and nozzle size (FlashForge printers will try to print .gx files that aren't made for them - they won't work well!)

Calibrate your printer / level the bed.

Wash the bed with dishwashing liquid and dry - even if it looks clean (there could be oils etc from your fingers)

If printing PLA, increase the bed temperature to 60-70 degrees celsius

Try changing to a new roll of filament - this is more art than science. Filament is weird and gets affected by lots of things: bad batch, absorbs water, different colored filament of the same brand etc.

Watch the first layer go down - if you can see that the surface is not completely flat (i.e. bits of plastic sticking up or bumps), it could be a partial clog in your nozzle or an insufficiently levelled printbed. The bits sticking up may get caught by the nozzle on the second layer and detach it. If you have another nozzle try swapping that in, or else you could try cleaning your nozzle with a cleaning needle. Alternatively try recalibrating the bed.

Use a glue stick or hairspray

Generally with the textured PEI plate included with the Flashforge 5MPro, glue stick shouldn't be necessary. However, in some cases

Use a raft

Factory reset your printer