Windows 10 Mail App

I like this app very much indeed. I have 6 mail accounts added to it and get a notification whenever a new mail is received by any one of them.
A blue envelope icon is added to my taskbar, which I can click any time to read mails received by each one of these accounts.
I can also send mail from this app, but never do, I prefer to use the actual email account.

PROBLEM !
Only my Outlook.com email - a Microsoft account lists all the SENT messages - the other 5 accounts including Gmail do not list SENT items. I have fiddled around and read the web and checked the settings on this app with no luck.

QUESTION ?
Does anybody know why SENT mails are not showing on all my accounts except Outlook.com ?
For 5 non-Microsoft accounts to fail out of 6 means it is a common problem - one which I have so far failed to resolve.

I find it disturbing that all 6 accounts list Inbox mails but only Windows Microsoft Outlook.com lists Sent mails.
THAT sounds highly irregular.

If I understand that right, you want to Sent mail folder is always there in the list? You can add it to favorites, by clicking on More, right click to wanted folder and select "add to Favorites"

Out of 6 accounts listed in my Mail app only Outlook.com shows the contents of the Send folder, all the others do not.
No problem with Inboxes, all 6 accounts show the full contents.

Rather odd that the only account showing contents of the Send folder is a Microsoft email.

What is the version of your Mail app? My says Version 16005.13214.41002.0. Check the Store if there is any update available

Not sure, but think I had some problems with sent items a week ago (or so). It is working fine for me with 2 MS accounts, gmail, and my business account. All are Exchange, except gmail is IMAP.

Not sure if Windows mail can store pop3 sent items.