Signing in is only possible for users who have been activated. If you didn’t activate your users upon their creation, you can do that at any point later by following this procedure. You can easily select one or more users and send the activation email to them. If you prefer to activate a user by generating their password, you can do that for a single user. 

Steps to send activation email to one or more users: 

1. In your directory, in the Users tab, select one or more inactive users whom you want to activate. 
2. Above the list, expand the Actions dropdown and select Activate. 
3. In the modal that opens, confirm you want to send activation emails to users by clicking Activate. 

Steps to generate a password for a single user: 

1. In your directory, in the Users tab, hover over the selected user and click Open. 
2. In the User details right panel, click the Actions button and select Activate. 
3. In the modal that opens, select the Generate password radio button and copy the generated password to send it to the user. 
4. Optional: If you want to require the user to change the generated password upon first sign-in, select the User must change password on first login checkbox.