Mircrosoft Office activation "revoked" after Windows 10 upgrade

Question

I upgraded my system from Win7 to Win10 (6 weeks ago) without any troubles.
On Win7 I had installed Office2013 with a volume license (key integrated in installer file), provided by my university. This install was activated okay and worked for years without problems.

By now however, whenever I start an office-application I get a warning that I have (by now) two more days to activate.
The text says "This copy of ms office is not activated // You have two more days to activate. Make sure you are connected to your company network, to activate the automatic activation. Your sys-admin can assist you with this. // CHANGE PRODUCT KEY // DISMISS // ERRORCODE 0x.."

When looking through Microsoft's pages, I found the following:
https://technet.microsoft.com/en-us/library/ee624355.aspx?f=255&mspperror=-2147217396

The Office 2013 client does not activate when it is connected to the network through an authenticated proxy

You have to be connected to the Internet to use MAK activation. However, if your Internet connection requires authentication, MAK activation won’t work and you’ll have to activate over the telephone. For more information about this issue, see Knowledge Base article 921471: Activation fails when you try to activate Windows over the Internet.

This is applicable in my case as I am connected to the web through a authentication-based proxy.
This is still a problem in some ways:

1. Why does it demand another activation now, an unspecific number of days after the upgrade
2. How am I supposed to activate it via phone, when I don't have a key (as said: it was integrated)

Solution

Why does it demand another activation now, an unspecific number of days after the upgrade?

It triggered a reactivation because, as far as Office is concerned, it's on a different computer. Microsoft's Software Protection Platform (SPP) uses a number of metrics to determine whether or not the product has been moved to a different computer. Unfortunately, the Operating System version is one of those metrics.

If you had an internet connection that it could've activated over, it would have just done it automatically without prompting you. But because of your proxy, it can't and it's been 28 days since the SPP was "tripped" (probably from the point where you ran it the first time after the upgrade).

How am I supposed to activate it via phone, when I don't have a key (as said: it was integrated)?

You shouldn't need the key. Provided this is a legal copy of the software, the product key was typed in when the OEM installed it. When you call Microsoft to activate by phone, they will ask you for a challenge code which Office will give to you (they will show you how to get it). They will then provide you a response code to type back in for the activation process. The product will then be activated without needing the key or an internet connection.

Comments

[Ramhound]

I presume the reason it requires activation is because the installation wasn't moved perfectly. You need to determine what the key is then activate by phone.

[Mark]

Also by now I tried activating it via proxless network : I hooked my phone to the PC and launched Word. But same difference