Finding a working authorization code for is currently difficult because Adobe officially shut down the activation servers for this software in 2017 . Because the servers are offline, the standard "Internet Activation" process no longer functions. Current Status of CS3 Activation
Since CS3 is nearly 20 years old and technically incompatible with modern operating systems (like Windows 11 or macOS Sonoma), you might consider these options: authorization code for photoshop cs3