I have done the following:
1. disabled all plugins
2. Switched to default twentyfourteen theme
3. Cleared browser cache
4. reactivated plugins one by one
Here's what I discovered:
with default theme, all plugins deactivated AND clearing of cache, it works in all browsers.
So, I reactivated child theme, tested, and it worked.
Began reactivating plugins one by one and when I got to "Broken Link Checker" plugin, it quit working. Deactivated it, cleared cache and it still wasn't working, so I had to go through steps 1-4 above and now it's working. (without the Broken Link Checker plugin enabled)
Fixed for now. Thanks.