Internal server error on first setup

I’ve mentioned this on another thread, but actually it’s a new topic so I though It best to start again. I’m trying to set up Nextcloud on my PC. I’ve installed Apache 2.7, MariaDB 10.4 and Php7. I got my webserver working properly with a test website and test php script.

I’ve installed Nextcloud from the repository of the linux system I’m on (Manjaro). and followed the instructions in the Arch Wiki for Nextcloud (and the Manual).

When I go to localhost I get a Nextcloud screen with ‘Internal Server Error’

When I look in the var/log/httpd/ I see a block of errors which begins with this one

[php7:warn] [pid 495] [client ::1:39738] PHP Warning: fileperms(): stat failed for /usr/share/webapps/nextcloud/data/nextcloud.log in /usr/share/webapps/nextcloud/lib/private/Log/File.php on line 140

I haven’t pasted the whole block because there’s a lot of data that I don’t recognise and I don’t know how much of it might be unwise to make public. It’s basically a repeat of the above four more times interspersed with ‘cannot create file’ , ‘permission denied’ and ‘no such file or directory’ issues.

My whole /usr/share/webapps/nextcloud directory is owned by ‘root’ but group ‘http’, which my webserver user is also in and the group has RW access to the whole directory recursively.

How can I further investigate the cause of this problem?