Don't panic! 

If for some reason the email with an address didn't arrive in your inbox, or you loose it, simply go to your Sent postcards and click the ID of that postcard: the address will be shown to you once again. 

Unfortunately, some email servers consider Postcrossing to be a spammer and thus discard the emails. This is beyond our control but several things can be done to overcome this situation. Please try this:

1. check your email account Junk/Spam folder;
2. change your email address in the profile to another one in a different provider (gmail.com is known to work);
3. make sure that the domain @postcrossing.com is in your list of safe senders;
4. in the very odd case that all the above options failed, please contact the webmaster for help.