My first thought is to double check your internet connection. Reset the modem/router. Double check system settings on your PS. Make sure you have a good connection. Next step is clearing ESO's save data. Don't worry you won't loose any progress because everything is saved on their servers and not on your console.

If neither of those work, I really don't know what else to suggest. You can try contacting support and see what they suggest. I don't know much about playing from SEA. Perhaps someone else might be able to give some insight.