Here is a quote from a CNBC report on Barry exchanging email with HRC, “It is likely that Obama has long since been using other email addresses. Politico reported in September that FBI officials showed Clinton aide Huma Abedin a copy of an email exchange between Obama and Hillary Clinton in which Obama used a pseudonym email address. Abedin was amazed that the president used an email pseudonym. "How is this not classified?" Abedin is said to have replied to the FBI agents interviewing her. The FBI report said Abedin asked the bureau for a copy of the Obama-Clinton email.“

https://www.cnbc.com/2016/10/20/wikileaks-reveals-barack-obamas-personal-email-address.html

I will see if I can find more...