[Error 500 - new install - centos webpanel]

I am getting an error 500 on new (haven't yet been) installed revive.

Upload the files via FTP, went to the web address where it was uploaded, then Internal Server Error

This is the apache log

[Tue Jan 24 02:12:07 2017] [error] [client 162.158.231.87] SoftException in Application.cpp:249: File "/home/marvin/public_html/ads/index.php" is writeable by group
[Tue Jan 24 02:12:07 2017] [error] [client 162.158.231.87] Premature end of script headers: index.php
[Tue Jan 24 02:13:51 2017] [error] [client 162.158.231.87] SoftException in Application.cpp:249: File "/home/marvin/public_html/ads/index.php" is writeable by group
[Tue Jan 24 02:13:51 2017] [error] [client 162.158.231.87] Premature end of script headers: index.php

This is on a cloud vps on digitaloceant with centos webpanel  0.9.8.145

Apache version: Apache/2.2.27
PHP version: 5.5.30
MySQL version: 5.5.47

I know the caveats of running on a custom server (instead of CPanel). But I can't find any info where to move forward.