If you are receiving this error message when trying to login to your Sandbox account please follow the steps below:
If your sandbox accounts were upgraded to 2.0 recently, then your Account ID's would have been changed to something similar to 3839275_SB1 (ending with SB1 SB2 etc). You will need to change your Sandbox Account number in the Admin Portal to the new Sandbox Account number.
To find the new Sandbox Account Number in NetSuite go to:
Setup > Company info. >Account ID
NOTE: Your existing Sandbox templates will not transfer automatically. if you need them transferred contact Celigo support and an Engineer will be able to transfer them on the backend.