Website in Maintenance Mode

Good day,

No question, this is a great and powerful plugin, I have used for many years without any problem.

Today, a major problem happened which I have not faced before, after installing the copy of WordPress I logged in to the backend and it did not have any problem, the problem resides on the front end putting the website in maintenance mode as scheduled maintenance.

I have tried many options to remove this mode, the .maintenance is not there, removed a file previously active maintenance.php, and even looking into the code but nothing was helpful.

Wondering why this is happening and how to fix it?

Thanks,