Error message "Zwift encountered the following error. ......."

The following message pops up when i try to execute the program.
“Zwift encountered the following error. An exception occurred during a WebClient request. Object reference not set to an instance of an object. If the problem persists please contact Zwift Support.”

Does anybody know how the deal with this issue?
Is it a .Net framework issue?
Did tried to re-install .Net framework 3.5 but still the same and also tried several times to re-install zwift as well.