Permalinks. That little setting buried at the bottom of your WordPress Settings options. It seems like such an insignificant thing, but it can have a lot of impact on the functionality of your site and The Events Calendar plugin.
We generally recommend using "pretty" permalinks with The Events Calendar. Without getting too technical, some of the functionality of the plugin depends on these more-readable URLs in order to work.
What's the difference between "pretty" and "ugly" permalinks? There is a nice breakdown of the differences in the WordPress Codex, but you can see the difference right away in the following examples:
- Ugly: http://example.com/?p=N
- Pretty: http://example.com/post-name
Isn't the URL much nicer in the second example? That's because it's a lot easier to read. Any permalink setting besides the Default one is considered "pretty".
In additional to looking nice, the pretty permalinks are helpful for ensuring The Events Calendar plugin functions properly. Though any pretty permalink option will work, selecting the "Post Name" option is typically your best bet.
It's also worth noting that permalinks are helpful for troubleshooting issues with the plugin as well. For example, let say you head over to your calendar page and--what?--nothing is there! A common fix is to "flush" your permalinks by going to Settings > Permalinks and simply clicking the Save Changes button. If you run into trouble, resaving your permalinks is one of the first troubleshooting steps to take.