Debug: MailMessage can't see value. Expression Activity type 'CSharpValue`1' requires compilation in order to run. Please ensure that the workflow has been compiled

I use GetOutlookMailMessages Activity to get mail.

To do debug, For Each mail(MailMessage) can’t see value.
It shows Expression Activity type ‘CSharpValue`1’ requires compilation in order to run. Please ensure that the workflow has been compiled.

It can run, but it can’t see each mail(MailMessage) value in debug mode.

item - MailMessage type

item.From - MailAddress - Expression Activity type ‘CSharpValue`1’ requires compilation in order to run. Please ensure that the workflow has been compiled.

item.Sender - MailAddress - Expression Activity type ‘CSharpValue`1’ requires compilation in order to run. Please ensure that the workflow has been compiled.

all properties of item(MailAddress) are showing this message - Expression Activity type ‘CSharpValue`1’ requires compilation in order to run. Please ensure that the workflow has been compiled.

Why can’t it see the value?
How to show their values?

Thank you!