The most likely reason for a ‘Service unavailable’ error on AiSensy is a problem with the WhatsApp Business Platform servers. To find out if there is any ongoing maintenance or server downtime, check the WhatsApp Business Platform Status page. If there are, wait until the service is back online and try again. If the problem continues, you can also try refreshing the page, verifying your internet connection, and getting in touch with AiSensy support.