Debugging using log output

[simond]

Good day,

I am relatively new to espoCRM, which is why I need lots of console output to understand the information flow through the application.
I use version 5.6.0.
To receive more information, I set the logging-level to 'DEBUG' in the data/config.php file.

However, on my local machine I do not receive any debug logging output.
In fact, not even custom error output, which I tried to print like this

GLOBALS['log']->error('out in method x'); 

To confirm my own code being adapted, I modified the method 'processValidationField' from /application/Espo/Services/Record.php.
The added code to output to the log does not work.
However an extension of the BadRequest exception message to

throw new BadRequest("Not valid data. Field: '{$field}', type: {$type}., entity:"); 

does yield an extended HTTP Response message.

Does anybody have an idea what I am doing wrong?

Best wishes and many thanks in advance
Simon