Formula SUM from different sheet not working in iCloudNumbers

I'm trying to create a formula =SUM from a different sheet. I'm able to do this in Numbers but now that I am accessing and updating my sheets from iCloudNumbers, I can not complete this with a cell from a different sheet. Typing in manually doesn't seem to work either. Ex. =SUM(Table 1::D50). Any help would be appreciated.

[Re-Titled by Moderator]

Original Title: iCloudNumbers