Unable to Connect to Backend error

Apologies for adding to an old post but we have a similar error - when a user attempts to upload a files to a project, it failes with error: "Unable to connect to backend." Not sure when this would have started, it is possible it has been like this for a while, but no-one had tried uploading a file until now.

We are running Xerte 3.14.5-11 (updated 24/04/2026)
PHP v8.2 - all required extensions appear to be selected

I've set $development flag to true in config.php. Not sure if I am looking at the right error log - have found xerte/error_logs/debug.log which only showing this when upload is attempted:

2026-06-17 14:56:20 /home/[installation]/public_html/xerte/website_code/php/database_library.php177Running : SELECT * FROM sitedetails
2026-06-17 14:56:20 /home/[installation]/public_html/xerte/website_code/php/database_library.php125 parameters: Array
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Any advice would be greatly appreciated, thanks.

Hi, I wonder if anyone has any suggestions for my previous post above.  We are still struggling with this issue.  Sorry for posting again but with the forum being offline for a while I fear it may have been overlooked.
Really appreciate any help with this as it's impacting our Xerte use quite significantly.
Thanks.

Hi Takeshi,

With $development enabled, do another attempt to upload a file and then go to the error logs of the webserver (I assume this would be apache2).

Tom