Although Sony abondoned us, the PSN service is still alive and there are still loads of multiplayer games which are still running fine, like Call Of Duty, Killzone, Need for speed and more. While using PSN with a hacked PSVita can sound dangerous, it's not. We have no record of bans other than people playing a game before it was released. (Even trophy hackers weren't banned from PSN although unofficial PSN leaderboard websites banned them. It's a wonder if Sony erased our existence of their minds). So you can play online and use your main account on your PSVita. But you may face some problems.
This particularly affect 3.60 users. I don't know for what reason, but there's a fix for that. Just reset HENkaku like I said on the 3.60 problem page, set the spoof back to the latest firmware version and reinstall your plugins.
It appears that Sony recently changed something in their servers. If you're getting this error it means that you have ITLS enso. Disable and renable it when you have done your business with the settings.
The culprit is usually your network. Delete any custom DNS servers you have set in the WiFi settings, and try switching to another network (like a mobile hotspot for example)