Hello, yes, i finally accomplished to install after several try & error attemps during at least 4 days!! :-o
By default the errors of PHP/Apache when running Nextcloud and any PHP script are dumped to here, and i can confirmed to you that it was very helpful for me:
Furthermore, Nextcloud echo its error messages to the second file above, i think so. Well, i don’t remember very well which of both files above where, but it’s one of them. In any case, both are useful to be checked during installation.
You must know too that you can modify the config file of Nextcloud:
and set 2 interesting values:
'loglevel' => 0 (0=Debug, 1=Info, 2=Nothing)
'logfile' => '/var/log/nextcloud.log'