Zwift does not start / white screen

Hello,

yesterday my Zwift didn’t start.
When I start the launcher, only a white window appears, but nothing happens. Never happenend before.

I already uninstalled Zwift twice, but unfortunately that didn’t help. During the first start after new installation, the white screen / window also appeared, only it showed “serching for updates” and “update” (or similar) for some seconds on the bottom of the otherwise completely white window, then the window is only white and nothing happens.

I also tried different graphic settings on my laptop (Intel internal graphics and Nvidia GeForce graphics), but this didn’t help either.

Any ideas?
Thanks in advance