use get_access_token in signed_session, to ensure the Authorization token in the session is not expired
@@ -105,7 +105,7 @@ class MicrosoftAppCredentials(Authentication):
if not self.microsoft_app_id and not self.microsoft_app_password:
session.headers.pop("Authorization", None)
- elif not session.headers.get("Authorization"):
+ else:
auth_token = self.get_access_token()
header = "{} {}".format("Bearer", auth_token)
session.headers["Authorization"] = header
