Hi simon, not sure about this one, but maybe is like you said and you're loading an amount of data that you're server can't handle. For this I would say that the best solution is to check if it's necessary to have all your data load at once. From that you may find dashboards or users that you can dispense of.
In any case it depends of the requirements you have to fullfil.
If you have more information about it perhaps someone could help you a bit more than me.
Hope it helps.
Cheers,
Andrés
