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Two Step Sign-In - Frequently Asked Questions

Please see below our list of frequently asked questions in relation to Two Step Sign-In

Using Two Step Sign-In

When will I need to use Two Step Sign-In?

When you are connecting the services listed below from a network outside of Trinity, i.e. your 4G phone connection, your own home WiFi or the WiFi of an eduroam partner.

  • Microsoft 365
  • VPN (staff only)
  • Core Portal
  • Trinity Web Systems
  • MyZone
  • SITS (staff only)

What do I need to use Two Step Sign-In

You will need to have your mobile phone close by and powered on.

Verifying via phone

If verifying via phone, you will receive a text message with a code or else a phone call.

If you are outside Ireland, we recommend you have data roaming switched on.

Verifying via Microsoft Authenticator app

If verifying via the Microsoft Authenticator app, you will need to have the app installed on your phone.

What will I expect to see when using Two Step Sign-In?

You will see a request screen pop up during sign-in.

Depending on the type of verification you will then receive either a:

Verifying via text message

Once you receive a text message to your phone with a verification code, paste this code into the request window and click Verify

Verifying via phone call

Once you receive the phone call, answer the call and press the # key. You can then hang up.

Verifying via Microsoft Authenticator app

To verify via the Microsoft Authenticator app, you will either receive an app push notification to your phone asking you to 'Approve' or you will be asked to enter a code from your the Authenticator app into the TSSI request window.

Why do I have to provide a phone number?

You will need to receive a text to your mobile to verify your identity. There is no extra cost for receiving SMS messages, even if you are travelling within EU member states. As from June 2017 you will ‘roam like at home’ and pay the same prices for calls and texts as you would at home.

Where is my phone number held?

When you add your phone number during Two Step Sign-In registration, it is held on a secure server in Microsoft. The server is within the EU as part of our Enterprise Agreement and is GDPR compliant so your information is protected. Your number is only held for the purposes of sending you validation codes and will not be used for any other purpose. It is not visible to any other users or applications in the service.

What if I change my phone number?

Please see change the verified phone number.

Can I add a second number?

Please see add an alternative sign-in method.

I am getting verification codes sent to me, but I am not trying to sign-in!

Don't panic, the good thing about two step sign-in is that no one can access your account unless they have the verification code.

Work through this quick checklist to see where the request might be coming from:

  1. If you are on Trinity campus, make sure that your devices are connected to the wired network or TCDwireless WiFi network.
  2. If you are off campus:
    • On your laptop check that your VPN is on and connected
    • If you don’t have VPN on your laptop
      • Check that you don't have a browser window open that is connected to /
      • Check that you don’t have Teams or Outlook open as they could be requesting a connection in the background.
    • On your smartphone/tablet:
      • Check that Outlook or Microsoft 365 apps are not running in the background.
      • Check that you don't have a browser window open that is connected to /

Once you know that none of your devices or apps are trying to connect without your knowledge, report this to Service Desk ( but be assured that without the verification code, another party cannot access your account.

Will the verification texts always come from the same number?

Sometimes the sender ID of the verification text message may be different, if you are worried about whether to trust a verification message, note that they are only sent in response to a login attempt. So if you are not logging in to email or Microsoft 365 outside Trinity networks and you receive a verification text, your account may have been compromised and you should change your password and report this to Service Desk (

Here are some examples.

How do I use the option 'Don't ask again for 30 days'?

During the two step verification process you can choose the option 'Don't ask again for 30 days' or 'Stay Signed in?'

Only use these options on a secure device that only you can access.

Selecting these options will save your login details, on the device (computer/tablet/phone) you are currently using, and you won't be asked to login/verify again for 30 days on that device.

After 30 days you will need to complete the two step login process again.

If you run into difficulties, work through this quick checklist to try to resolve the problem:

  • Check your Browser (Chrome/Safari/IE).
    1. Close your browser, making sure to close all windows/tabs.
    2. Re-open you browser and go to
    3. You should be prompted to login
  • Check your Teams app
    1. Sign out of your Teams app
    2. Open the Teams app
    3. You should be prompted to login

If you have restarted all your Microsoft 365 apps and you are still having problems logging in please contact the Service Desk (

I travel a lot and don't always have access to 3G/4G networks to receive texts, any advice?

In situations where you may not be able to receive text messages but you have access to Wi-Fi, setting up the Microsoft Authenticator app as an alternative sign-in method is a good option.

Please see Changing/adding sign-in methods.

App Passwords

What is an App Password?

An App Password is a 16-character password which is linked to your account and used on apps which do not work with your normal username and password combination.

Such apps are the Mail and Calendar apps that come with your iPhone and Android device.

How do I create an App Password?

Please see add an alternative sign-in method.

Why am I repeatedly asked for my password on apps other than Outlook?

If you are using a mail or calendar app other than Outlook on your smartphone, you may find that you are repeatedly asked for your password when signing in, in this case the password that is required is your App Password.

Please note: IT Services strongly recommends you access your email either by using Outlook (on desktop or phone app) or by logging into The Outlook App is available from the Google Play Store or Apple App Store for smartphones, and comes as part of the Microsoft 365 suite when installed from for your laptop / tablet.

Using other mail clients to access your email will require the use of App passwords, this is a 16-character password generated during Two Step Sign-In setup, and used instead of their usual Trinity computer login password when signing into the mail client.

For example, using the Apple Mail Client outside the trusted Trinity network requires an app password. This can be confusing if you are using a laptop both on the Trinity Network and outside. The first time that you connect your device to a network outside Trinity, the Apple Mail client will not connect and will prompt for a password. If you enter your usual Trinity computer login password you will be repeatedly prompted for a password, with no indication of why the Trinity computer login password is not accepted. In this instance you must enter the App Password.

I am being asked to create an app password as well as another method

In some situations, while setting up TSSI, you may be asked to set up an app password as a second step in TSSI. An example would be the below screen.

If this happens, once the setup has completed, you can delete the app password method from Microsoft 365 Security info page.

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