User error when trying to create an account

This was reported by 2 of our users.
please see attached image

Hello,

got to email setting and provide yours SMTP server http://take.ms/TkyjT

https://backendless.com/docs/android/doc.html#messaging_sending_email_rest

I don’t understand. what is my smtp server?
this is a new issue and we haven’t changed such settings before

Hello Tal,

This error means that your email configuration at the moment is incorrect. Sergey has attached link to documentation explaining how to configure it properly. When configuration will be complete you may test by hitting a corresponding button. Attaching an example of correctly configured email settings
http://support.backendless.com/public/attachments/4b45184961f7d4ae1dabb215c25226f8.png</img>

Regards Anton

So today I have already a certain IP address set as the SMTP.

how do I know if I need to change it and what to change it to?

What is your application id?