Hi Shivam.garg
How did you create a mar file, did you use make mar utility or downloaded it from devtest portal ?
Try the following ,
1. check if the VSM or VSI file is corrupted, if its not corrupted then,
2. Delete the Virtual service mar file from VSE Deploy folder and redeploy. if you still were not able to deploy, then
3. create a mari file and deploy the mari file.
If everything is good and you still face the issue then restart of devtest vse service might help.
To know more on the issue check the vse.log file
Thanks,
Venkatesh