Exactly the same problem. Both on an iPad (ios11 public beta 9) and iphone6 (iOS 10.3.3) but it's been happening on both devices for quite a while. I cannot share to EN from Chrome. Period. Window pops up, compass fills, then white progress circle just spins. I hit cancel and get a plain white "note could not be saved" pop up.
Also, and I don't know if this is related, both devices have, and have had for asking as I can remember, a persistent banner on the home screen icon (the red circle with a one in it) that I cannot clear. I can't find any pending messages, alerts, etc. inside the app or on the desktop version.
I've been premium since 2010 and this is the first real problem I've had but it's a doozy.