This is most likely a temporary thing and you can just try to do the same thing again.
If you have made changes to your details, try logging out and then back in again.
Please contact us quoting error-500 and describing the events leading up to this error and the hardware and software you use. If you were trying to contact another member, please include the details of the organiser or exhibitor. This information will help us to investigate the cause of the error.
Thank you for your assistance, we apologise for any inconvenience caused.