Hi Matt,
Did it work before or is it the first time you’re using the plugin?
Beside Safari browser acting weird, the label generation may be stuck if the browser is blocking popups. Either by default (maybe it asked you whether to block it and you accepted) or some Ad blocker browser extension is blocking pop ups.
This is because the labels page is generated on the server, then the browser opens a new tab for it. Browsers consider such tabs as “popups”.
You can check whether that is your case:
== Check Google Chrome popups ==
Go to browser Settings > Under Privacy and security click Site settings > Click Pop-ups and redirects. See if you site is listed under Not allowed to send pop-ups. Remove it from that list if so and try generating labels.
== Check Ad blocker extension popups ==
If you do have such extension installed in your browsers, clicking the extension should show what it is blocking on that page. Maybe popups is one of them.
I can investigate this issue further if you contact me via Facebook messenger (there’s a link on my website) to exchange screen shots. First, I’d like to see if there are any errors in your browser Developers Tools console.
Dima