Unfortunately we seem to be having some IT problems again with the LPCXpresso IDE free edition activation site. We have notified the appropriate team and hopefully these will be resolved shortly
However, your alternative to waiting for the activation site, would be to use MCUXpresso IDE which has superseded the old LPCXpresso IDE product. MCUXpresso IDE does not require you to activate in order to use the Free Edition.
For more details of MCUXpresso IDE visit - http://www.nxp.com/mcuxpresso/ide
Regards,
LPCXpresso Support