Hi @Aysha Baloushi ,
Welcome to our forum.
we can't recall the sent items even if the user didn't read the emails.
As a know, there are many limit except Read/Unread of recalling a message normally(such as if the users are in an organization and others), it's suggested to first refer to this article to check if your condition could meet it : Recall or replace an email message that you sent
Also, based on my research for hybrid exchange environment, I found a related article that mentioned "Recall only works for messages on the same Exchange farm" , which may cause "When a user with an on-premises mailbox recalls a message, it's recalled from all the users whose mailbox is on-premises. but not for the users who are on the cloud. Users in the cloud can recall messages sent to other cloud users but not to the on-premises users.", for more information, please refer to this article : Recalling Sent Messages.(Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.)
If that's not your case or you still need further assistance, please feel free to post back.
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