Hello,
i have the following problem with my Woocommerce instalation.. Every time i try to complete a order in the shop, i get redirected to the Wordpress Login Page instead of the WC Thank you page. I already tried to unceck all of the Registration Options in the Settings but with no change.
I also tried to disable all of the Plugins.. The only one left which i really can't turn off is WordPress MU Domain Mapping which i need to actually get he Domain in my WP MU Installation.
Feel free to test it on http://www.miyu-chan.de/shop/ i will delete the order afterwords.