I've had this happen before. If you click on the error it should give you a more specific error code. Try searching for that error code.
The solution for me was to delete my Google account and re-add it (Settings, scroll down to your account, click it. Click your account again, click the three-dotted menu towards the top, Remove account). Somewhere along the line a key or certificate gets out of date or becomes invalid and Play Store cannot recreate it.
Random question, but do you use two-step authentication?