Error Message Configuration - Display error if required string is not contained in input

[ddiesel]

I have an application that takes a text input of an email address. I want to restrict the application to only accept internal email addresses. I think I can use the Error Message tool but I need help configuring it. I can't find much information here on error message configurations.

1) What is the syntax for writing "does not contain '@companyname.com' "

2) Is there an alternate (better) way to accomplish restricting this text input?

[GavinAttard · Accepted solution]

Hi

!Contains(string, target)

I think this should work in terms of methodology. 

kr

[ddiesel]

@GavinAttard worked perfectly! Thank you!