URGENT: Unable to validate Acrobat Pro DC Serial Number...

I purchased this software last night and followed the steps when installing.  During the installation, the serial number worked fine. When I tried running the software for the first time, and after logging in with my Adobe ID, I was prompted to enter my serial number again. This time, it was rejected ("We are unable to validate this serial number...").  Can someone please contact me immediately?  I looked through the threads and noticed that others have encountered this issue, but I did not see any helpful solutions.