Recently he goes to Israel and lets the Israeli prime minister make Jerusalem the capital of Israel. There were enough tensions between them and the Palestinians as it was.
The sole source that continuing conflict lies with the Palestinians who refuse to take part in any meaningful peace protest. They paid $360m to terrorists last year, money that was supposed to be invested in infrastructure. It's time the international community stopped it's closet anti-semitism and dropped support for them - treat them like the cancer they are.
Trump actually did what many, many presidents before him (including Obama) promised to do (recognize Israels decision). Refusing to accept it would be equivalent to the US deciding that they don't accept London is the capitol of the UK.