@benjy123: Please can you confirm the model number of your watch, and when you purchased the device? Also, are you attempting to purchase Samsung Care+ via the link below and, if so, at what stage do you encounter the internal server error?
Thanks for confirming that, @benjy123. If you haven't done so already, I recommend trying to complete your transaction using a different web or mobile browser.
If you continue to encounter the server error, please call the Samsung Care+ Support Team on 0333 0091 717.
I have the same issue trying to register for Care+ with a Tablet get right to the end and then get Internal Server Error. tried on both Google and Firefox. The tablet is only 1 week old