Server is down after changing machine type in Google Cloud Platform

I changed my machine type(GCP) by stopping the instance, after increasing the machine type I restarted the instance and now server stopped working, the website is down now.
Upgraded from 1 vCPU, 1.7 GB memory to 2 vCPU, 4GB memory.
And if I select other than 1 vCPU, 1.7 GB memory, the webserver doesn’t respond.
Also, I can’t access SSH from a web browser it gives me an error that “Connection Failed. We are unable to connect to the VM on port 22.”

Log: https://pastebin.pl/view/2af02149

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Author: Sandeep Kumar Giri