Assuming you have the '365; subscription version, there was a comment in the Magix Vegas Pro Video forum about discontinuing VP-365, I assume it would be the same or similar to Sound Forge. Search Vegas Pro forum.

Otherwise contact Magix Customer Service
If you need help requesting a support ticket, see this recent comment:
https://www.magix.info/us/forum/wrong-serial-number--1259553/#ca1608151