MESSAGE:ACCOUNT NOTICE We've run into a problem with your Office 365 subscription and we need your help to fix it. (Reactivate button) SOLUTION:1- Have the user close ALL windows that are open.Log in as an tenant admin, go to the user and log that user off of all Microsoft services.Try again- If that doesn't work go to step 2

2- I understand we are facing activation issues on the machine. We were able to isolate the issue by following the below steps ::

--Signed out of the Office applications

Launch any application(say Word or Excel)à File à Account à Sign out à Yes

--Remove the credentials from the Credential Manager

Search for Credential Manager in the control panel à Windows credentials à Microsoft Office 15/16 à Remove the credentials

--Remove the Identities folder from the Registry

HKEY_CURRENT_USER\Software\Microsoft\Office\16.0\Common\Identity\Identities and deleted the "Identities" folder

Try again now, if it does not work go to the next step -

--Run the scripts mentioned in below by running the command prompt as an administrator

Office 2016:

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cscript.exe "%ProgramFiles(x86)%\Microsoft Office\Office16\ospp.vbs" /dstatus

cscript.exe "%ProgramFiles(x86)%\Microsoft Office\Office16\ospp.vbs" /unpkey:XXXX

Office 2015:

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cscript.exe "%ProgramFiles(x86)%\Microsoft Office\Office15\ospp.vbs" /dstatus

cscript.exe "%ProgramFiles(x86)%\Microsoft Office\Office15\ospp.vbs" /unpkey:XXXX

XXXX is the last 4 digits of the Office key that is displayed from the /dstatus switch

--Launch Office applications and activate with Office 365 credentials