iPhone iPad and Windows Outlook 2016 do not synch deleted email

User has iPhone, iPad and Dell Windows 10 with Outlook 2016.
The three devices are not synchronizing deleted emails properly.
They have Comcast email which shows IMAP setup on all three devices.

If they delete from iPad, message is removed from Outlook but not iPhone
If they delete from iPhone, message is removed from Outlook but not iPad
If they delete from Outlook, message is not removed from either iPhone or iPad

What should I check?   Thanks.
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Eoin OSullivanConsultantCommented:
There are some SETTINGS in the email client which control how the deleted messages are handled.
On the iOS devices change how soon the Trashed email is deleted .. it may be set to NEVER or
Open the app called Settings on the iPhone's Home screen.
Go to Accounts & Passwords
Tap the desired email account in the Accounts list.
Tap the IMAP section to go into the Account details.
Tap Advanced at the bottom of the screen that opens .. now you can control where deleted messages are placed, how they are handled and to control WHEN they are deleted tap Remove in the Deleted Messages section.
Select After one day. (Other selections include After one week, After one month, and Never.)
Tap Save.

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Patrick BogersDatacenter platform engineer LindowsCommented:

Delete command are not send in real time when a message is deleted, so delays can occur.
If all 3 mail clients have imap it should/will sync.....

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