Hello. My name is***** can help you with your question.
You should not have to do anything special to access Google from a new Internet provider. But since your Google account has stopped working since then, what I would suggest doing is removing the account and re-adding it. When you add it back, it should set the server settings for you. If necessary, you could do a reset of the Kindle and then set it up from the setup screens again. To do that, you just hold the power button down for 20 seconds and when it resets after 20 seconds, let it start up and go through the setup wizard.