I am on travel and my innkeeper's network is blocking outgoing mail. How can I send mail from my laptop?

Error message

Notice: Trying to get property of non-object in ldap_authentication_init() (line 223 of /var/www/xlr8/lpl/sites/all/modules/ldap/ldap_authentication/ldap_authentication.module).

Some innkeepers and internet service providers prevent you from sending mail by blocking port 25. If you are on travel and cannot send mail from your laptop, you can configure your email client program to use port 587 for outgoing mail, instead of port 25.