We help IT Professionals succeed at work.

Exchange - The security certificate has expired or is not yet valid

Last Modified: 2014-08-10
Hi Guys

I have a client who is using Microsoft Office 365 Exchange, 2 of the users Outlook keeps asking for a password and will not connect to exchange.

From either machine we can logon using a browser but Outlook will not connect, keeps asking for password. When I first start Outlook I get a Security Alert... "The security certificate has expired or is not yet valid"

When I view the certificate, it has Valid from 24/03/2012 to 24/03/2014 and issues by the local server in the office. Yes we run SBS2011, they use to have exchange locally but migrated to Office 365 a couple years ag0 - having said that the exchange services were still running on the local server which I have since stopped and disabled.

Another thing to note is that the 2 machines having the problem are new machine which were added to the local domain a few weeks ago, there are 3 other machines in the office connecting to Office 365 without any problems?

Any ideas?
Watch Question

hecgomrecNetwork Administrator

Yes!... the other machines most likely where update/upgraded to the 365 so their credentials.

Besides, the certificate being really expired the fact that outlook keeps asking for password could lead to few things, so let rule 5 for now;  Make sure the Network card on the new machines is set to be always on by turning of the power Management features. Also, make sure the right credentials are entered and the user can choose to save these.

One of the most common reason why outlook ask for credentials is a lost of communication to the server, in this case, this could be cause by wrong driver for the network card, cable problems or a bad network appliance (switch, router, etc.)


I don't think there is anything wrong with the network card, I was logged on remotely while doing my testing and I was on the machine for hours without a drop out.

I'm pretty sure it has something to do with the fact that we are running SBS2008 and Exchange & IIS services were running on the server - I suspect for some reason these 2 clients may be looking at the local SBS server for exchange services??
hecgomrecNetwork Administrator

Try to check the settings in one of the computers that is connecting to exchange and compare it against the ones not connecting and see if the server's name are the same or not.

If they are both the same, then they are locating the server properly, if not just changed it to the good one and try.

Have to try to create any of the accounts that is working elsewhere on any of these machines? or vice versa?
This one is on us!
(Get your first solution completely free - no credit card required)


It is what worked

Gain unlimited access to on-demand training courses with an Experts Exchange subscription.

Get Access
Why Experts Exchange?

Experts Exchange always has the answer, or at the least points me in the correct direction! It is like having another employee that is extremely experienced.

Jim Murphy
Programmer at Smart IT Solutions

When asked, what has been your best career decision?

Deciding to stick with EE.

Mohamed Asif
Technical Department Head

Being involved with EE helped me to grow personally and professionally.

Carl Webster
CTP, Sr Infrastructure Consultant
Empower Your Career
Did You Know?

We've partnered with two important charities to provide clean water and computer science education to those who need it most. READ MORE

Ask ANY Question

Connect with Certified Experts to gain insight and support on specific technology challenges including:

  • Troubleshooting
  • Research
  • Professional Opinions
Unlock the solution to this question.
Join our community and discover your potential

Experts Exchange is the only place where you can interact directly with leading experts in the technology field. Become a member today and access the collective knowledge of thousands of technology experts.

*This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.


Please enter a first name

Please enter a last name

8+ characters (letters, numbers, and a symbol)

By clicking, you agree to the Terms of Use and Privacy Policy.