The administration's policy is to pressure Israel on Iran and the Palestinian issue by sending a message that Israel is not a "friend". This is also the reason behind the unsubstantiated claims regarding spying. If there were cases they would have named them. We have to get used to the fact that the current US admibistration is hostile to Israel.
PM postpones Israel-Germany summit marking 50 years of diplomatic ties (Haaretz)
from the article: U.S. denying visas to Israeli defense officials, report says