You get this error when you are accessing the VMware LabManager url from the remote console, but the same has worked for you till yesterday,
This error occurs mostly because of the low space in C:Drive,
You can remove the previous Log Files from the system than it will work fine.
You can go the the Location
in this you can delete the Old files or you can copy it somewhere else and remove from C:Drive Location.
After removing it now check the LabManager URL.
it will work like charm!!