It's a red x

@Jason-Bottomley Then you're entering the serial number incorrectly. You can find your correct serial number in your customer account at Magix.com. Simply login with your e-mail and password and look under My Products.

I've already done that several times and checked it several times to make sure it is correct

@Jason-Bottomley Try copy-and-pasting the serial number from your account. This way you avoid typos (for example whitespaces or mistakenly entering the letter O instead of the number zero).

If this doesn't help, I'm not sure what the problem might be. Maybe you need to contact customer support at infoservice@magix.net and ask them for help.

Thanks guy's, I've tried everything suggested on here but still not working

You may want to try deactivating Sound Forge AS 17 on the PC you are having trouble with. Then reactivate. To deactivate SF on a PC online, log into the Magix Service Center> My Products. Choose your product, select "Show More Details" and choose 'Deactivate' on the PC. If that does not help, email Magic Customer Service: infoservice@magix.net .
As you are probably aware, one license can activate a perpetual version of Sound Forge 17 on two (2) PCs simultaneously. Only one (1) PC the can be activated at a time with the '365' subscription version.

btw, welcome to the Magix Sound Forge users community @Jason-Bottomley.

Hi raad, thanks fella but I've already tried that too. I had to reset my laptop as just installed Abelton live and was short on space in hard drive, I've also just bought a 49 key midi keyboard to use with it as now starting to remix, been a dj for 30 year's so thought I'd best start remixing.

@Jason-Bottomley

Thanks guy's, I've tried everything suggested on here but still not working

Please send me a private message with a screenshot where you try to enter your serial number in the Activation window after you open Sound Forge. Maybe I can see a typo. But please don't post the screenshot here in the public forum.