"Timeout / unknown" status in an asynchronous process execution

So I have a case where we update user data in an external service in an asynchronous way. We have a table with users - each row gets a separate user with a separate request, is handled separately. We get the async responses from the external service by polling.

However, there can be a case where we don't get a response due to an error in the external service, however, it might have completed the request but just isn't responding properly to our polling which then results in a state where we don't know the actual state (did the data update or not).

Has anybody worked with such a situation and what would you do?

• Just show the row as in error (red) state: timeout
• Have a new state of "unknown/yellow" - request sent but response unknown;
• Also ask the user to manually check and change the status to red or green?