How can i fix RequestTimeout when deploying Azure ARM template

Question

I am working on the Managed application applicaiton that has "Microsoft.Web/sites" and i use "Microsoft.Web/sites/extensions" with a source code in zip file. It used to work well, but lately I've started to receive "RequestTimeout" during the "Microsoft.Web/sites/extensions" deployment process. Here's the info:

{
    "status": "Failed",
    "error": {
        "code": "ResourceDeploymentFailure",
        "message": "The resource provision operation did not complete within the allowed timeout period."
    }
}

I've tried to install my managed app into other regions: US2, US3, EUwest2. I had the same issue there as well.

How can i fix this and why this started to happen?

Thanks in advance for any help.