Hey I am not able to setup business unit in Dev Sandbox for account engagement. Could anyone please guide me? Also, My org has Enterprise edition

Hi @Divya Agarwal,

Go through these articles and make sure you have a proper license for that. if any required for Account Engagement.

1) Account Engagement Business Unit Setup Admin click here.

2) Create Account Engagement Users (imp if not created, I think without this we can't add Business Units anymore) click here. 

Please let me know whether this works for you or not.

Thanks & Regards

Ronak Sharma