To be able to use referral codes, you will first need to make sure to use the latest Tapfiliate tracking code. The landing page code should use the 'detect' method instead of 'detectClick' in order for referral codes to work.
After this update is complete, you need to make sure you are using either 'Query' or 'Hash' tracking method in your program settings.
Finally, enable referral codes in order to use them, otherwise, your affiliate URLs will be generated as 'https://your-site.com/?a=123-abc&tap_s=345-def'.
Note: if you're using the redirect tracking method, please contact our support chat, as this method is slowly being phased out.