Hi Team,
Sometimes you can face issue like customer has responded to WhatsApp message but still service window will show inactive under 24 hours.

Reason
Reason for this can be if phone number is not saved with +91(or any country code) at lead level, so as per the converse configuration at backend, it will always try to match the number with country code whenever the lead will respond and for these cases number will not with the responded number, so service window will not be changed to active.

Solution
Update the phone number and add country code.
