I am using the file upload action to copy a file from an approval site to a storage site. Sometimes the storage site does not exist in our office 365 tenant. The action has the ability to write to a variable if the upload is not successful, but the workflow suspends if the site does not exist. Interestingly, it is not trivial to test whether the site exists in O365 - I saw some posts where they use call web service, but this returns unauthorized because it does not pass credential tokens to the web service automatically. The destination is in another site collection.

Any idea how I can test for the existence of the site prior to the file upload, or how is the success variable in this action supposed to work?