Hello again,
I have just solved the problem. This may help others too. In the log file which I attached above, there was a line:
Library/Application Support/Local/run/router/nginx/logs/error.log" failed (13: Permission denied)
I located that error.log file. Right click the file, Get info, when the file info box opens, go down to Sharing & Permissions, change the Privilege from Read Only to Read & Write.
That’s it.