Make sure you have updated all your drivers.
If you are using Windows 10 you can also try running Steam as Administrator.
If your name is using characters other than English ones, try changing it to English only characters.
Generally make sure your console is clean and dust free.
Freezes and Intermittent disconnects
If you are experiencing freezes during the spinning skull or intermittent disconnects from PSN, first rule out any WiFi problems by connecting your PlayStation directly to your router with an Ethernet cable. If the freezing or disconnects do not occur when the PlayStation is connected via Ethernet cable, then try these tips that may improve your WiFi:
1) use a short WiFi SSID with only alphanumeric characters, no spaces, no symbols
2) use a short WiFi password with only alphanumeric characters, no spaces, no symbols
3) turn on Bluetooth pre-emption if your router has this feature, and try other wireless interference reduction features
Make sure the WiFi antenna on the rear of your PS3 is not near any metal or water pipes or other wireless devices like mobile phones or Bluetooth speakers that will interfere with the WiFi signal.
If HellDivers freezes during the SYNCING SAVEDATA step, try deleting and reinstalling the HellDivers game (back up your save data beforehand).
Check your error codes
Check what error code you are getting and try Googling it first. Sometimes this can be a PlayStation console error and there's not much we can do about that. In that case you should contact PlayStation customer support.
If the error is related to save data, try this solution.