Hi Guavity,
Thank you for your query. Please note that the Message Recall feature in Outlook is only available within an organization and does not work for recipients outside the organization. Additionally, this feature is supported only within Outlook itself.
Even if the recall process shows as successful, the recipient may still receive the email if they are either not using Outlook or are outside your organization.
In situations like this, the best course of action is to send a follow-up email to the same recipient, politely informing them that the previous email was sent by mistake and asking them to disregard it.
I hope this clarifies your concern. Please feel free to reach out if you have further questions.