Why am I having issues updating my phone to Windows 10?

[Windows Central Question]

So in the past week , my Lumia 720 has downloaded close to 4 GB worth data to update to Windows 10 through the Insider app. I've had a couple of space issues and all, but it all went away until yesterday. First I got the error (80188308), then after I clicked on "check for updates" it started downloading, but it stopped at 88% saying "You need to connect to Wi'Fi to download the update" I am connected on WiFi. I've used different outlets, restarted and rebooted the phone. Nothing worked. What do I do?