I cannot activate SDL Trados Studio 2017 Freelance Plus on a second PC.

I cannot activate SDL Trados Studio 2017 Freelance Plus on a second PC. I get the error message: "Activation failed. Please provide the quantity equal to or less than the remaining quantity 0."

This is a big problem is I have a deadline today. I tried to live chat with SDL support but just got some useless, cost-saving copy/paste bot - how infuriating.

Could anyone please advise why I am suddenly no longer able to use my 2nd licence (I have used it in the past without a problem)?

Thanks...