Outlook Bypass Validation of E-Mails - Outlook 2016

[Rizwan Habib]

My employers have upgraded all the computers from Outlook express office outlook 2007 and 2016
We have an issue,

There are two accounts setup, internal and external.

For our internal email it is set-up in the following manner,
email@company

However, using Office 2007 or 2016 the following message appears, "Microsoft Office
Outlook does not recognize email@company", it then offers a list of
addresses to choose which normally suggests using the
address or says "(no suggestions)".

Is there a way to ignore or bypass the validation of emails and send
regardless?

Thanks!