Blank screen after upgrade v3.8.1 to the latest is v4.0.1

old version 3.8.1 was running fine until i do the upgrade. when upgrade to v4.0.1 it show blank screen. so i need to restore back to v3.8.1

php using is 7.0

Are there any errors in the logs?

No, even i try with the new domain it will show blank screen. i try with the new installatio there is same issue. inform the webhosting company there ask me come to the deveoper

please see the reply from the technical.

Have you checked both the web server logs and the application logs (storage/logs/laravel-error.log)