When your account was migrated it created new links for your current client sites. You will need to send them this new link. The easiest way to do this is to create an email template with the client site link in it notifying them of the new link.
First create the email template. Settings > Templates > Emails > Click the green New Template button.
Name the template, give it a subject and in the body make sure to add the Client Access Link variable.
Next, go to each active job and click the green actions button to and Send Email.
Choose the template you created. You will see that it inputs the client info for you. You can now click send email and move to the next active client.
Please use the orange chat bubble in the bottom right corner of your ShootQ account to chat with support if you have any questions.