If you get prompted for your user credentials and your Gmail account is listed offline, your
email user name probably contains a "dot".
To fix the problem, remove the "dot" from the name so e.g.
You don't have to change anything in your gmail account, just remove the dot in the macOS Mail app. Dots don't matter in Gmail addresses.
See you at Web, MicroProfile and Java EE Workshops at Munich Airport, Terminal 2 or Virtual Dedicated Workshops / consulting. Is Munich's airport too far? Learn from home: airhacks.io.