i have a problem, in the past days we have made new email accounts with mydomain.com and a lot of users have hotmail.com or outlook.com accounts, the question is how can i syncronize all the contacts and old emails between two or more accounts?, for example i have changed the settings of mydomain.com account to send mails from the outlook.com, and in the outlook.com i forwarded the mails to mydomain.com, but i can't see my old mails and i'm going to login only with mydomain.com for now on.

Greetings you all.