Mentioned in  on Core SVN:
Twenty Twenty-One: Check for navigation element before using it.
Created ticket #52773 on Core Trac:
Twenty Twenty-One Theme - "Can't read property querySelector of null" ...
Created a topic, Js events on my site not working due to error from Caldera Forms, on the site WordPress.org Forums:
Below is the console error. When Caldera Forms is acti…
Posted a reply to File upload is not compatible with Safari v11.1, on the site WordPress.org Forums:
Facing the same issue.
Created a topic, Great Product., on the site WordPress.org Forums:
Very easy to use & works great.