Remember what the activation message was before? If it was "activated by digital license" (unlikely for a corporate), then they should activate automatically when connected to the internet, unless there have been major hardware changes (such as swapping motherboard). This is exactly the reason why cloning the disk of identical hardware computers will NOT activate, because the motherboard is the same model, but different S/N along with the rest of motherboard devices. If the message was "activated by your organization", then they have VLK (aka volume keys, not OEM or retail) and were either indeed activated by your business server, or they were ILLEGALY activated! In the first case, just ask your IT to activate them again via the respective service running on your server. In the second case, we cannot tell you how to illegally reactivate them, you have to find out yourself. The simplest legit way is to buy a cheap key for each device and change the key to activate, not sure if you can buy it from Microsoft Store at a reasonable price. The alternative legit way is to contact Microsoft, if all the computers are in a single corporate of course, and buy volume keys which should be cheaper than OEM or retail keys. If you have all these computers in a computer shop and you intent to activate Windows and sell them, then your only legit method it to buy OEM keys from a Supplier. Most will do a better price for more than 10-15.
PS: To find out which type keys you have (retail, OEM, VLK) open an PowerShell as Administrator and execute slmgr /dlv then check the Description line.
