"In the end, a senior Israeli official said, the issue was removed from the agenda due to American opposition." - Haaretz This was the "excuse" a couple of days ago. Today, Egypt is the "guilty" party! Both are fake excuses. Even with tense relations between Qatar and Egypt, there would have been no harm for Egypt to allow reconstruction in Gaza. As for the "American excuse", I don't see why the US should object to having Qatar gain some prestige. Qatar is a good friend of the US and has many US soldiers stationed there. Qatar also tries to be friendly to Iran, its neighbor and potential trouble-maker, but this is natural. If the UN passes a sanction resolution against Iran, Qatar will comply like other nations. I simply don't believe that the US objected to Qatar's involvement in Gaza, especially since the US is opposed to the siege Gaza is under. Most likely, this is some excuse by Israel, and the real reason is that Israel wants to continue with the siege.
from the article: Israel spurned Qatar's Gaza offer after Egypt protest