Upfront not working as it should

After installing wordpress on a Google Cloud Platform Development server, Upfront Doesn´t work as it should. Can´t change images on a theme, everything "sticks" to the screen. Have used Upfront on similare servers without problems.

Server Specs:
type wordpress.jinja
bootDiskSizeGb 10
bootDiskType pd-standard
enableTcp443 true
enableTcp80 true
installphpMyadmin true
machineType n1-highcpu-2
network default
wordpressAdminEmail
zone europe-west1-d

First problem with upfront.