Unable to add google calendar to iCalendar

I helped someone this week with their Mac with a similar issue to yours. They were trying to add a gmail address to their Mail through the Internet Accounts preference pane and the process was stalling at the password verification page.

After waiting patiently but in vain for it to accept the password and complete the process I restarted the Mac and attempted again to add the gmail address. On this occasion the addition succeeded. Whatever impediment we had the first time was cleared by the restart. Perhaps that might succeed for your calendar problem?

Glad to help. If it solved your problem you might consider clicking the solved button beside my solution for future readers.

Of all the uses one has on a computer a difficulty in connecting to some personal information, such as calendars or email, for me is especially irritating and any time I have to do something with Google lowers my expectation that a process will be smooth.

Another example is the transition Google forced users to make from the Backup and Sync software to the Google Drive for desktop. If a committee was formed to design a difficult experience for a user they could't have come up with anything more clunky. I know this is what PC users put up with all the time, but really! Making Mac users do this rain dace to get a simple syncing device working?