Using Freshdesk, you can send an auto-response notification for Out Of Office or after Business Hours. To meet this requirement, set up an automation rule under Admin > Workflows > Automations > Ticket creation > New rule.
Sample rule:
Conditions:
In tickets > If Created > During > Non-Business Hours > specify the business hours
Actions:
Send Email to requester (customize the Subject and Body)
You can also reorder the rules you've added as described in the below video:
https://www.youtube.com/watch?v=Gt2VWBeuBU8&list=PLsYJ3BsyR4qGFujlW0iDtOBOf4IPVsAqt&index=14