Can't Receive eMail from Outlook Users

Can't Receive eMail from Outlook Users

Prior to 3 months ago, we were able to receive email from @co.pg.md.us for at least the last 2 years. The users on @co.pg.md.us are Outlook users. They can receive email from HostedRecords.net but we can't receive email from them. This started 3 months ago. Can you please research this. Thanks