Mailbox size Your Conversations page can hold a lot of messages: For free members, the size limit is: 5,000 For paid members, it's unlimited. If you're seeing an error that you have a full mailbox, you may want to upgrade to a paid account to get more space. 🎉 Fun fact: even if you only purchase one month and cancel right away and go back to free after that month, you'll keep the bigger mailbox size. We're just nice like that. If you're trying to send a message but are getting the error that they have a full mailbox, unfortunately, there isn't any way to get around that. You'll just have to wait until they upgrade to get more space.