unable to SSH to GCE instance after writing to partition or make a change in /etc/fstab

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unable to SSH to GCE instance after writing to partition or make a change in /etc/fstab
I have an VM instance-1 that was wrongly created with two separate partition sda1(boot),sda2(contains cpanel accounts ) in /dev/sda.
Recently i have succeeded in transforming instance-2 ( snapshot of instance-1) with a single /dev/sda1 and additional disk /dev/sdb for the cpanel accounts.I could now easily resize them for additional space,
however i went thru lots of trial and error to achieve it, as everytime i make a change in /etc/fstab or after deleting that /dev/sda2 partition, i was unable to SSH with error Connection Failed, and we are unable to connect VM on port 22.
Even if i have trashed the /etc/fstab , still I should be able SSH to rectify any wrong entry,however GCE is not allowing this, please help
gcloud compute ssh <YOUR-INSTANCE-NAME> --zone <YOUR-INSTANCE-ZONE> --ssh-flag="-vvv"
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Try to SSH to the instance with the following flag to get more details during the SSH process and share the output.
gcloud compute ssh <YOUR-INSTANCE-NAME> --zone <YOUR-INSTANCE-ZONE> --ssh-flag="-vvv"
Please make sure to remove any sensitive data before sharing the information.– Milad Tabrizi
2 days ago