I have a problem with activating Acrobat DC 2015 (Classic)
I had to reinstall my computer. Windows 10-1909, now I cannot deactivate this computer in my account. I only see the serial number. Now Acrobat is "activated on too many computers". I'm only use this PC. Apparently reinstalled too often without deactivating the activation in Adobe Acobat.
If you are stuck because of a perpetual license system/setup which is no longer available so cannot be deactivated, then you may have no choice other than to contact Adobe Customer Care directly to request a reset of the activation count for your license... They do not support email contacts; only via live online chat (in your web browser) or telephone, depending on your region: