Nitro Pro 10 activation problem

[AD1 0]

I have the same problem as above - am trying to activate Pro 10 on a new PC. I downloaded the current version of Pro Trial, and am trying to activate it with my Pro 10 Serial Number.

My serial number is rejected by the Activation process, as ti is deemed invalid (I've copy/pasted, so it's not typo errors). I have previously de-activated the previous version on https://licenses.gonitro.com/prd/portal. I now have 0 activations and 2 permitted, but still I can 't activate 

What's the solution, please?

Thanks,

AD