If you search well & master solution of KDETools OST to Office 365 migration tool. It is the able to convert emails, mails, and etc. from OST to Office 365 account. Try to install The ost to office 365 converter Software to export ost to office 365 file conversion. This ost to office 365 software helps you to export all ost to office 365 accounts with import file data items like emails, calendar, contacts, journal, attachments, tasks, etc. The converter software to Export ost to Office 365 account free online, office 365, Live Exchange server, Gmail, OLM, NSF, EMLX, vCal, vCard, EML, MSG, HTML, Zimbra, PDF, MBOX, and etc.

https://www.kdetools.com/ost/office365/
ost to office 365 migration tool