ok, it was a firewall issue from the server. that is open now, I have verified the key, but upon uploading of a font, I still get an error, saying
API Key invalid. Please make sure API key is associated with this domain.
IMPORTANT : Premium Key that were bought before 24th Sep, 2018 will no longer work in Use Any Font 5.0. So please get your replacement key here. You don’t need to pay again. Use your old Premium Key as Discount Coupon and it will apply 100% discount. We are sorry for the inconvenience caused.
but underneath it says that the key is active. I have also checked all the boxes below, still doesn’t work