Is your WiFi speed 20 megabits per second (Mbps) or faster? – Knowledge Base

Are you on a WiFi connection with an upload connection of 20 Mbps or faster?

If not, you may notice that your plans or tasks may take longer to load.

Tip: You can identify the speed of your WiFi by going to http://www.speedtest.net/ or by downloading the 'Speed Test' app in iOS Speed Test app or Google Play Speed Test app

If yes, and your upload connection speed is 20 Mbps or faster, and you notice synchronization issues, then proceed to the next steps in this Help Center Article.
If no, keep in mind that using cellular data is a much less reliable and more faulty way to sync data. The typical bandwidth capacity of the cellular connection can vary immensely - even from minute to minute.

We typically recommend that you connect to WiFi with a reliable connection of 20 Mbps or faster.

These articles provide more information about resolving synchronization issues.