Redemption code is invalid

A redemption code must be converted into a serial number. Sign-in at the link below and enter the numbers and letters. The resulting serial key will have 24 numbers (no letters) commencing 1057 for Photoshop Elements. You then launch the Editor, click licence this software and enter the 24 numbers.

https://redeem.licenses.adobe.com/getserial

Where was it purchased from?

What version?

Is the redemption code for your operating system?

Have you previously used the redemption code?  It can only be used once to get a serial number.