There is no IP address for Manager that would be relevant. You need to specify your own SMTP credentials. Have you read this Guide, including following links in it to any applicable second-tier Guides: Email transactions and reports | Manager?
If so, and you still have problems, provide the information here: Troubleshoot email issues | Manager. Be sure to include screen shots of any error messages. “…is not working…” does not provide any basis for anyone to help you.