If you see the error "Sorry, but we're having trouble signing you in. AADSTS50105" when signing in to ContactMonkey, it means your organization's IT administrator has not granted your account access to the ContactMonkey application in Microsoft Entra ID. This error comes from your organization's own security settings, not from ContactMonkey.
Note: Microsoft Entra ID (formerly Azure Active Directory, or Azure AD) is Microsoft's cloud identity and access management service. Your IT team uses it to control which users can sign in to applications like ContactMonkey.
What does the AADSTS50105 error look like?
The full error message reads:
Sorry, but we're having trouble signing you in.
AADSTS50105: Your administrator has configured the application ContactMonkey ('[app ID]') to block users unless they are specifically granted ('assigned') access to the application. The signed in user '[user email]' is blocked because they are not a direct member of a group with access, nor had access directly assigned by an administrator. Please contact your administrator to assign access to this application.

Why does the AADSTS50105 error happen?
This error happens because your IT administrator has set Assignment required? to Yes on the ContactMonkey enterprise application in Microsoft Entra ID. With that setting enabled, only users (or members of groups) who are explicitly assigned to the application can sign in. Your account is being blocked because it has not been assigned, either directly or through a group.
Because this is controlled by your organization's identity settings, only your IT administrator can resolve it — ContactMonkey Support cannot grant this access on your behalf.
How does my IT admin fix the AADSTS50105 error?
Share these steps with your IT administrator. They assign the affected user access to the ContactMonkey enterprise application in Microsoft Entra ID.
- Sign in to the Microsoft Entra Admin Center at
https://entra.microsoft.com/ - Go to Enterprise Apps and select ContactMonkey
- Click Users and groups in the left sidebar
- Click Add user/group
- Select the affected user, or a mail-enabled security group that the user belongs to
- Click Assign
After the assignment is saved, the user should be able to sign in to ContactMonkey normally. Assignments can take a few minutes to take effect.
The user already has access, but still sees AADSTS50105 — what else could cause it?
If access was already assigned and the error continues, check these two causes.
- The user's email address changed. If the user's email or username was updated, the assignment may still point to the old identity. Your IT admin should confirm that the user's current account is assigned access to the ContactMonkey enterprise application.
- The user is signing in to the wrong region. ContactMonkey hosts data in separate regions (US, EU, CA, AU), each with its own application ID. The application ID shown in the error message indicates which region's app was used. If it does not match your organization's data region, the user selected the wrong region at sign-in. To fix this in the Outlook 365 Add-in, follow these steps.
Important: If you do not know your organization's ContactMonkey data region, reach out to support@contactmonkey.com.