This is due to too many functions being updated simultaneously. You can avoid this by staggering the queries so that they are not all fired at the same time. 

To do this, go to Tools: Scripts: Script editor, and in the Supermetrics function (in older versions called "getData"), above the line which has the UrlFetchApp, insert these two rows:
var randnumber = Math.random()*5000;

With this in place, the queries will wait for a random time of between zero and five seconds before being updated, thus it's less likely that you would hit Google's limitations. If you still have trouble, you can duplicate the second row, this will cause a wait of between zero and ten seconds (and of course, you can put this line there as many times as needed, if you're still hitting the limit).