Hi Sachin,
Could you have updated the *.wyu files on your servers without also updating the *.wys files? Are you using the built-in wyBuild uploading mechanism (you should) to ensure all the correct files are being uploaded? Otherwise perhaps something is being corrupted.
You might also benefit from doing the usual latest OS/system updates, run a virus scan, etc.
If it's still not working please provide more info about what OS/version/environments you're working in, steps you're taking, and such so we can try to help further.
Best,- PaulwyDay Support