Upgrade 8.2 to 8.3 blank page

Hello,

the upgrade process worked fine without any errors.
After the upgrade I tried to clear the cache as mentioned in https://docs.suitecrm.com/8.x/admin/installation-guide/upgrading/:

./bin/console/ clear:cache
Dose not work, so I tried
./bin/console clear:cache
Seams to work but I face an other error: " There are no commands defined in the “clear” namespace."

How can I clear the cache manually? Can I delete al files and folders in ./public/legacy/cache ?

I cant log in because I receive just a blank page.

Solution:
max_execution_time = 300