This can be caused by a few things, as below:
The mobile account hasn't been set up for the engineer
The Username is misspelt either on the server or on the device
The Password entered is incorrect
Only users with access to SME Mobile Administrator will be able to make the following changes, if you do not have this then contact your IT and provide them with this article.
Open Administrator from your list of Access application, it will be the grey icon with tools
Sign in with an account with Master permissions, such as SA
Click Users
Double click the user from the list, if they exist
Enter the correct username and password
Save your changes
Pass the details along to the engineer to get them signed in
To create a new user:
On the System tab, click Users
Click New User.
Type the User details.
User ID: A unique ID for the User. This could be the Engineer Code or the User ID from Service Manager.
User Name: The User’s email address.
Password: A password for the User to connect with.
Profile: The Profile for the User.
Enabled: To be checked if the User is enabled.
Administrator: To be checked if the User is to be an Administrator.
On the Linked Users tab, click Insert.
Add the Linked User:
AMS Database: The database to link the User to.
User Type: Is the User an Engineer or a User.
User ID: The User ID of the User to link the account to.
Add additional Linked Users as required.
Click Save.
Click Save & Close. The User should now be able to log into the chosen databases via Service Manager Mobile.