Hi,
This issue may be related to the anti-virus programs, to verify this, is it possible to temporarily disable it for that user?
If Office 365 is activated via proxy, make sure these addresses and IPs are added as exception, then check the result again.
https://activation.sls.microsoft.com
http://crl.microsoft.com/pki/crl/products/MicrosoftProductSecureServer.crl
http://crl.microsoft.com/pki/crl/products/MicrosoftRootAuthority.crl
http://crl.microsoft.com/pki/crl/products/MicrosoftProductSecureCommunicationsPCA.crl
http://www.microsoft.com/pki/crl/products/MicrosoftProductSecureCommunicationsPCA.crl
https://odc.officeapps.live.com
https://ols.officeapps.live.com/olsc
http://officecdn.microsoft.com
go.microsoft.com
office15client.microsoft.com
sls.microsoft.com
65.52.98.231:443
157.55.44.71:443
157.55.160.109:443
157.55.192.81
168.62.30.34
I hope the information is helpful to you. If the issue is not resolved, please let me know more details such as the exact error message that says it cannot be activated.
Regards,
Melon Chen
Forum Support
Hi,
Just checking in to see if the information was helpful. Please let us know if you would like further assistance.
Regards,
Melon Chen
Forum Support
Hi,
I'm marking the reply as answer as there has been no update for a couple of days.
If you come back to find it doesn't work for you, please reply to us and unmark the answer.
Regards,
Melon Chen
Forum Support