'Google servers are temporarily overloaded. Your message was not sent. Please try again shortly' Resolving this sporadic error spread across the globe especially for G Suite user.
Officially there is no way to store and secure your your Google Keep notes using password protection, however, multiple online third party apps can help. You can also store in Trash can just in case.
Transfer files wirelessly from PC to PC and/or PC to smartphone and vice-versa without any USB or data cable. Share the files at blazing speed using WLAN.
You can resolve the Gmail queued and failed delivery error with basic troubleshooting steps like clearing app cache, adjusting the sync setting, relink Google account, and making sure that background data is enabled.