This plugin hasnt been tested with the latest 3 major releases of WordPress. It may no longer be maintained or supported and may have compatibility issues when used with more recent versions of WordPress.
This plugin creates two widgets: one a list of events from a meetup group (by ID or URL name, for multiple groups use IDs); the other shows details about single event (by ID) with a link to RSVP — using OAuth if keys are specified, otherwise just a link to the event on meetup.com. Does require at least an API key (which it asks for on the settings page).
Extract meetup-widgets.zip to meetup-widgets & Upload that folder to the /wp-content/plugins/ directory
Activate the plugin through the ‘Plugins’ menu in WordPress
Set up your API key (and optional OAuth key & secret) in your General Settings screen.
Your site says the Meetup list of events can be added with either an API key or a URL. It seems this is not true. It cannot be added with a URL. In fact, there seems to be no field for entering a URL. If it's added in the space for the API, it only shows up in the widget as "add a valid API key."
Additionally, which of multiple API keys to use is confusing for many people, and your explanation is so abstract as not to qualify as an explanation at all.
I see that only one other person has asked for help with a problem with your plugin, and it was never resolved. I hope you do at least try to offer support.
Anyway, if it really were possible to use a URL rather than an API, this problem were not be occurring.... which it is...
support documentation is non exisitant.. maybe for a fulltime Dev perhaps...
its a bit like meetup RSVPs 75% no-shows, and a waste of organisers time and effort.
add full descriptions, frickin meetup (where i was directed for the API) was no better... no info at all what the "stuff" was I was to input was....
i can see why all meetup plugins fail in WP.
please improve n ill check back, and upgrade my rating.... really!!!! what were you thinking to put no decent info up?