suitecrm and joomla, both are accessible by http , or are you forcing https ?
into suitecrm aop config
you should have : http://joomlaurl
into joomla plugin portal plugin configuration you should have url for suite crm http://www.mysite.ext/SuiteCRM
and username password from a suitecrm user (try with your admin password first)
make sure also that you can send emails from suitecrm and also that you have well selected an email template for user creation email
edit: wait, your exempls shows \ in the url instead of / ie: http:\www.mysite.ext\SuiteCRM\ , typo ?