Problem #1: Many corporate email security systems put links contained in emails thorough vetting procedures to make sure they're safe. When they do this, they add lots of additional information to the link 'behind the scenes'.
Here's an example of the format of an original Registration page link:
Here's how that same link looks 'behind the scenes' after appearing in a recipient's corporate Outlook email program:
The link above will still send them to the correct Registration page when the original recipient clicks it in their email, but if they then attempt to copy the link and send it to others, or post it in social media, they often have problems (the link itself is more than 140 characters, for example).
Fix: Ask your recipient to right-click and select 'Copy' or 'Copy Text', rather than 'Copy Link' before using in other applications. What you're aiming for is for the recipient to paste only the original letters of the Seatrobot link exactly as it appeared in the email - not the 'behind the scenes' link their email program created.
Problem #2: Some social media apps, like Facebook or Twitter, can crop portions of your links when you post them, depending on how you insert them into your posts. This can result in your links going to seatrobot.com rather than your event page.
Fix: use a service like bitly to turn your Seatrobot registration / ticket page links into short-links before posting on social media.