I have setup a multistore:
The multistores are working fine. Now I have created a customer which is bound to the website b2b. The central customer configuration is per website.
But when I logon to b2b.domain.com with a customer that is bound to that site, nothing happens and I receive the login form again. The logfiles show no errors.
Please make sure your login form phtml file contains <?php echo $this->getBlockHtml('formkey'); ?>
You are might be getting this issue because of this.