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we are in a hybrid O365 and on premise exchange exchange (2016). And i am seeing that all external contacts that we add end up with additional &quot;other email addresses&quot; besides the correct (external primary address). The other addresses end with our domain. <br />
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Ex. Josmith@abccompany.com will be shown as the primary email - external contact<br />
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in the email options however I will see something like this, <b>josmith@mycompany.com</b> and <b>abccompany@mycompany.mail.<wbr />onmicrosof<wbr />t.com</b><br />
<br />
The problem now is that if i need to add an internal user that's named josmith@mycompany.com it does not work. It will tell me that josmith@mycompany is already in use. <br />
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how do I fix this problem? I can't delete the external contact.
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we are in a hybrid O365 and on premise exchange exchange (2016). And i am seeing that all external contacts that we add end up with additional "other email addresses" besides the correct (external primary address). The other addresses end with our domain. 

Ex. Josmith@abccompany.com will be shown as the primary email - external contact

in the email options however I will see something like this, josmith@mycompany.com and abccompany@mycompany.mail.onmicrosoft.com

The problem now is that if i need to add an internal user that's named josmith@mycompany.com it does not work. It will tell me that josmith@mycompany is already in use. 

how do I fix this problem? I can't delete the external contact.

O365 External contacts contain domain email address in &quot;other emails&quot; how to fix?

Exchange is the server side of a collaborative application product that is part of the Microsoft Server infrastructure. Exchange's major features include email, calendaring, contacts and tasks, support for mobile and web-based access to information, and support for data storage.

Exchange

A contact manager in its most basic form is a software program that enables users to easily store and find contact information, such as names, addresses and telephone numbers. Sophisticated contact managers provide calendar sharing features and allow several people in a company to access the same database. Some contact management systems have evolved into customer relationship management (CRM) systems to analyze and plan for an organization’s interaction with current and future customers.

Contact Management

Office 365 is a group of software plus services subscriptions that provides productivity software and related services to its subscribers. Office 365 allows the use of Microsoft Office apps on Windows and OS X, provides storage space on Microsoft's cloud storage service OneDrive, and grants 60 Skype minutes per month. Office 365 includes e-mail and social networking services through hosted versions of Exchange Server, Skype for Business Server, SharePoint and Office Online, integration with Yammer, as well as access to the Office software. All of Office 365's components can be managed and configured through an online portal; users can be added manually, imported from a CSV file, or Office 365 can be set up for single sign-on with a local Active Directory using Active Directory Federation Services.

O365 External contacts contain domain email address in &quot;other emails&quot; how to fix?

O365 External contacts contain domain email address in "other emails" how to fix?