I receive the following error when I try to retrieve the password on the ../wp-login.php?action=lostpassword page:
[08-Jun-2012 13:45:13] PHP Fatal error: Uncaught exception 'InvalidArgumentException' with message 'From address "" is invalid' in /home4/path-to-site/wp-content/plugins/postmark-email-for-wordpress/Postmark/Postmark.php:234
#0 /home4/path-to-site/wp-content/plugins/postmark-email-for-wordpress/postmark.php(173): Mail_Postmark->from(NULL)
#1 /home4/path-to-site/wp-login.php(229): wp_mail('email-address@...', '[Site Name...', 'Someone request...')
#2 /home4/path-to-site/wp-login.php(386): retrieve_password()
thrown in /home4/path-to-site/wp-content/plugins/postmark-email-for-wordpress/Postmark/Postmark.php on line 234
Does anyone knows what is causing this?