By now, it should be clear that using private email and messaging apps for official government business is not allowed.

National Archives and Records Administration no records response to our FOIA seeking communications with the White House regarding Ivanka Trump's use of personal email for government business, including regarding preservation obligations under the Presidential Records Act. (NARA-18-0890)

FOIA to NARA seeking communications regarding the preservation of any emails sent or received by Ivanka Trump using a private email account to conduct government business, including but not limited to correspondence about preservation obligations under the Presidential Records Act.