Eventually we find out that some of our feature services, layers, views in Arcgis online are not available, or showing unexpected behaviours. Quite often it is a temporary issue, aparently server issue solved by ESRI in minutes or hours.
But, in the meanwhile, we need to deal with unhappy / worried users, and have to answer for them, as we do not really know what the issue is.
ESRI people, how about reporting to all administrator users affected every time there is such a technicall temporary problem? Just an email explaining the issue and expected time to solve it would be fine.