loadURL server error (Raspberry Pi)

[ard jonker]

Hi folks,

I'm fighting with two RPI's and XTension. Using the RPIs to have this query string
	http://192.168.0.X/?Relay=8;value=1
let an i2c connected chip switch a relay, one chip commanding 8 (PFC8574), the other (PFC8575) commanding 16 relays, I can't get the 16-relays version RPI to work. At first I thought it was my 16-bit code on the RPI, but now I've set the index.php file to be identical to the 8-relay version working well on the X=233 RPI, still the X=245 gives an error in the XTension log.

What I have tried so far:
-I have identical code (the index.php file was copied from one to the other RPI), the web pages shown in Safari look exactly the same (except the behaviour in that there is no switching of relays because of the 16-bit i2c chip).
-The query string I display in Safari for debug reasons is the same (querystring is 'Relay=8;value=1'). Yet only the X=245 gives this error in the Log window:
	15/10/2019 11:00:25 loadURL returns server error (3 for url "192.168.0.245/?Relay=8;value=on"
-The other, X=233, runs flawlessly. I've made sure the folder /var/www has the same owner and group, and permissions on both RPIs.
-In both cases I also handle POST queries, they have the same query result and also output the same web page, e.g. POST, args is '8 ON'.

I've installed PHP and php-curl on both RPIs. Do I need other software that I have forgotten to install on the X=245 RPI which is essential for loadURL to work?

Any thoughts on why that RPI causes the error, and what that error may mean?

Thanks
Ard

Full log text after issuing the command using a screenshot, for I can't paste the clipboard somehow.
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