I did not try to buy during IEO yet. But I have seen many place that people are talking against the last IEO that they can not buy the coin despite of high speed internet connection. They also said site asking reload but after reload logged out.   Even people were complaing  about the issue by commenting  on their twitter. I don't think the right cause but may be had any problem with server. But if the problem will remain in the next IEO, then we can think it was a cheat.  Thanks