Let guest users manage CodeTwo email signatures for your Microsoft 365 organization

Problem:

You would like to allow a guest user invited to your Microsoft 365 tenant to manage email signatures, disclaimers & autoresponders on behalf of your organization in the Signatures app (app.codetwo.com).

Solution:

For security reasons, only users from your organization can be added as Signatures app admins. This also includes external users added as guest accounts in your organization. But for this to work, the guest user must be a member of a different Microsoft 365 organization (tenant) and exist in that organization’s Entra ID (Azure AD). Personal, non-business Microsoft accounts (e.g., Outlook.com) and email accounts from other providers (e.g., Google) are not supported.

To complete all the required steps, simply follow the instructions below. If you want to go straight to a specific section, use a link:

• Invite a guest user to your Microsoft 365 tenant
• Grant access to the Signatures app for a guest user
• Instructions for guest users on how to sign in to the Signatures app

Invite a guest user to your Microsoft 365 tenant

1. Sign in to the Microsoft 365 admin center.
2. Go to Users > Guest users and click Add a guest user (Fig. 1.).

Fig. 1. Inviting a guest user to your Microsoft 365 organization.

3. On the page that opens, select Invite user, provide the user’s email address in their home organization (mandatory), specify other user details and settings that you see fit, and finally click Invite (Fig. 2.).

Fig. 2. Configuring a new invitation.

Once the user accepts your invitation, they will appear on the Users page in the Microsoft Entra admin center. Make sure that ExternalAzureAD is displayed for that user in the Identities column, as shown in Fig. 3. Otherwise, your guest won’t be able to access the Signatures app.

Fig. 3. The guest user accepted your invitation and is listed on the Users page.

Grant access to the Signatures app for a guest user

1. Sign in to the Signatures app as an Access rights admin or your organization's Microsoft 365 global admin. Learn more about admin roles in CodeTwo
2. Go to Access rights and click Add > User (Fig. 4.).

   Important

   You need to specify an individual guest user here. Providing access to the Signatures app through group membership is not supported for guest users.

Fig. 4. Adding a new Signature rule admin in the Signatures app.

3. In the pop-up window that opens, select your guest user from the list and click OK, as shown in Fig. 5.

   Important

   If you cannot find your guest on the users’ list, manually update Entra ID CodeTwo cache, as described here.

Fig. 5. Choosing the guest user from the list of available Microsoft 365 users.

4. Your guest user will appear on the Signature rule admins list and, from now on, will be able to access the Signatures app by following the steps discussed in the next section.

Sign-in instructions for guest users

Now, your guest user can finally access the Signatures app to manage signatures, disclaimers & autoresponders for you. Ask them to proceed as follows:

1. Go to app.codetwo.com and click Manage signatures.
2. Important: If you’re signed in to your Microsoft 365 account in your browser, do not choose your account but click Use another account (Fig. 6.).

Fig. 6. Choosing to use a different Microsoft account.

3. Click Sign-in options (Fig. 7.).

Fig. 7. Accessing additional sign-in options.

4. Click Sign in to an organization (Fig. 8.).

Fig. 8. Choosing to sign in to a selected organization.

5. Type/paste the domain name of the organization which has invited you to their Microsoft 365 tenant and click Next (Fig. 9.).

Fig. 9. Entering the domain of the organization you're invited to (not yours).

6. Finally, click your account (if you’re signed in in your browser) or provide your credentials (for your home organization) to sign in to the Signatures app.

What if a user still can’t sign in with the guest account?

It may happen that CodeTwo’s Signatures app still does not allow a guest user to sign in due to security reasons. In such a case, ask the user to follow the additional instructions below:

1. Sign in to Microsoft 365's My Sign-Ins with the same account you want to use to sign in to CodeTwo’s Signatures app.
2. On the top toolbar, click your account icon and select Switch organization (Fig. 10.).

Fig. 10. Accessing available organizations in My Sign-Ins.

3. In the Organizations pane that opens (see Fig. 11.), select another organization you belong to and sign in to it.

Fig. 11. Selecting another organization to sign in to.

4. Back in My Sign-Ins, click Overview in the left menu or simply refresh the page. The portal will once again sign you in to the original organization.
5. Repeat steps 2. and 3. to switch the organization again. This time, My Sign-Ins should keep you signed in to the other organization.
6. Next, proceed to CodeTwo’s Signatures app and click Manage signatures.
7. In the Pick an account window that opens, select the Use another account option (Fig. 12.).

Fig. 12. Choosing to use a different Microsoft account.

8. Click Sign-in options (Fig. 13.).

Fig. 13. Accessing additional sign-in options.

9. Click Sign in to an organization (Fig. 14.).

Fig. 14. Choosing to sign in to a selected organization.

10. Type/paste the domain name of the organization which has invited you to their Microsoft 365 tenant and click Next (Fig. 15.).

Fig. 15. Entering the domain of the organization you're invited to (not yours).

11. Click your account (if you’re signed in in your browser) or provide your credentials (for your home organization).
12. At this point, you may encounter a “This page isn’t working” error. If you do, go back to My Sign-Ins and repeat steps 2. and 3. to sign in to the correct organization.
13. Try to sign in to the Signatures app again and repeat steps 7-10.
14. Finally, select your current account to sign in to the app (see Fig. 16.). This time, you should be able to access the application successfully.

See also:

• How to create a new signature rule
• How to quickly design your email signature visually using built-in templates