[Plugin: WP-Piwik] An error occured: Please check URL and auth token.

I’m seeing the error on a new installation of Piwik. The user has full privileges. In reading through other posts I noticed someone had reported this issue previously and you asked them to try the following:

https://YOUR_PIWIK_URL/index.php?module=API&method=SitesManager.getSitesIdWithAtLeastViewAccess&format=Html&token_auth=YOUR_AUTH_TOKEN

I used my URL for Piwik along with an appropriate auth token and it returned a value of 1.