Sorry for my reply. I'm only an F-Secure user (their home solutions).
It is a little be unclear what is your F-Secure solution. Does it F-Secure Freedome? Or what is validation code and where you try to use it?
But, basically, I think that concerns about subscription, licence-keys or related troubles are critical; and good to contact their official Support Channels directly (chat as example):
with enough information from you -> I think that Support Agents with abilities to provide proper advice about 'where to find validation code' OR re-trigger such information to you.
To discuss 'subscription' (licence, validation keys) troubles under community is not always reasoned.
In addition, possible to try find some helpful articles under F-Secure Knowledgebase:
resend the code to your associated email, which is linked with f-secure and then enter it, if you are unable to get the code try to mail them to manually send it.