I’m having the same/similar problem. The plugin is installed but when I head to the Streetshirts sub menu to complete the the installation I get the following error message after entering my details and clicking continue:
The requested URL /wc-auth/v1/authorize was not found on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
Any help/advice would be greatly appreciated.
I’m running WP v4.9.4 and up to date Woocommerce v3.3.4.
@davidealex: Unfortunately I still haven’t found a fix for this. As milah227 correctly spotted, I’ve gone about installing a new calendar instead.
A fix for the Events Calendar would be preferred though as I prefer the way it works.