Microsoft has upgraded their server to outlook.office365.com and now I can no longer receive mail on K9. I can send mail just fine but "fetching" no longer works. This is what the support team at Microsoft are saying --Today I got the update from our team that we also tested with K-9 mail client on android.
Seems we cannot configure this to works on K-9 client too. Our team recommend you may use workaround to another client which is: play.google.com/.../details
Also please note the server name has change to outlook.office365.com for IMAP/POP and smtp.outlook.office365.com for SMTP.
May I kindly suggest that you may use workaround for this issue? Also during the meantime you may contact K-9 for their support too as Microsoft cannot support all 3rd party mail clients.
For the list of products that we support is in here: office.microsoft.com/.../office-system-requirements-FX102921529.aspx
Thank you for your understanding.