Not receiving emails on Outlook from send email smart service

I am using Appian's Send Email Smart Service.
I cannot receive emails sent to emails with the domain names @outlook.jp and @outlook.com.
The Send Email Smart Service is green in the process model with no errors and the Send Email Smart Service is passing.

I have tried using Appian's Send Email Smart Service with Process, Process Model, Process Initiator, Process Designer and Custom Sender as the sender, but I cannot receive the emails.

The recipient email is enclosed with a toemaiaddress function.

We have also checked our spam folder, but there are no emails.

In Outlook, the domain of the emails sent from the Send Email Smart Service has been added to Safe domains.
No specific Outlook rules have been created.
The emails themselves are very small in size as they are test emails.

One concern is that when I use the toemailrecipient function, emails are sent for non-outlook email addresses, but I get the error "No valid recipients resolved" for outlook email addresses.