It was late in the evening, and the Egyptians asked for the call to take place the following morning. That morning, however, there was a misunderstanding. Israel believed the Egyptians were no longer interested in a phone call, and would suffice with a fax, whereas the Egyptian understood - and were annoyed - that Israel didn't want a phone call, and requested a fax instead.
Whatever, the end result was a perturbed Egyptian side and a break of contact at the highest level over what Shalom said was "complete and utter nonsense."
Thanks goodness they decided to give each other the silent treatment and not something more serious.