Do property taxes raise on existing mortgage every year?

[Alex Shaughnessy]

I bought a primary 8/2017. I was under the impression w/ a fixed mortgage your payment would stay the same. I got a letter from my lender saying its going up because of the escrow account. All I can think of is the taxes were raised. When I looked up my loan, I paid $4100 in property tax in 2018 and it says this year my property taxes are $5200. I thought it only adjusted when a property is bought or sold. Im exhausted so not sure if I articulated this as well as I can but if anyone can help w/ this confusion. The wait time for my escrow customer service is over an hour. Thanks in advance