Hi,
You can try below method, but i am not guarantee this will work, because from my opinion unless there is a specific keyword, else you cant detect it.
Below is the result i found via internet, you can try, but I cant guarantee this will work.
From Dynamics 365
There is someone stated below statement

I did find a field in Dynamics 365 , so perhaps you can try.

From exchange level
[View:https://stackoverflow.com/questions/1027395/detecting-outlook-autoreply-out-of-office-emails:750:50]