I send sms from Journey builder. If I answer SMS within the hour for a keyword, the response will come. If I answer after a couple of hours, then the answer to the keyword will be "There was an error processing your message.". I think it's because the response is timed out or something like that. How can it be extended?
This is due to the limits on 'MobileConnect Conversation Windows'. The default given for time between send and response is 60 minutes I believe, but you can change the configuration to a shorter or longer time. These are set at a Keyword level.
Here is the documentation on configuring a MobileConnect Conversation Window.