We recently were forced to implement protocols for free users due to an ongoing attack where spammers were using our application to send SPAM messages to thousands of unsolicited email addresses. Part of this measure was implementing a block on links included in outbound invitations. This block only applies to 'free' accounts.
While there may not truly be any links in your message, the system may be seeing part of your message as a link.
We know it's a pain, and we're working to scale back this defensive measure, but for now please ensure that there is a space or two after all periods (check the end of paragraphs, and add a space).
We apologize for the added hassle here. If you have any additional questions, please don't hesitate to reach out.
Tags: invitation, message, invitations, trying to send, link, links, error, can't send, no link in invite, invite, trying to send