My S7 OTA update is not installing on device?

[AC Question]

I have OTA update on my S7 of security updates. I download it and try to install it but on 32% and Android appear as a lay down with caution notification. Then my device restarted and it says that software installation failed. Then i go to smart switch to see if any update available for my device but smart switch is saying that i am updated to the latest software despite i have a OTA update that wont install.
Kindly help me with this.
Thanks in advanced.