Post successful installation of adobe acrobat 8 standard - Unable to apply the Serial Numbers, its gives an error saying unable to reach server.

Hello,

I am trying to install my adobe acrobat standard 8 on my Windows 10 laptop using the media link what i got it from the adobe site.

Its getting installed successfully, but post installation when i apply the Serial # to validate the licensing, its getting stuck.

am aware that this product is out of its life, but we have genuine licensing which we wanted to use it.

and more over our purpose is not more than just merging multiple pdf files.... Kindly do assist.