Export to Piwigo, Self Hosted, fails

I have the current version running on my server and no issues exporting to it from IOS App or any web browser on different platforms, but Darktable fails with “could not upload to Piwigo”. Login is correct and the albums are listed correctly, also if I choose a new album, t is correctly created on the Piwigo server. The fail occurs about 10 sec after “exporting 1 of x” is displayed on Darktable. Normal jpg export takes 40-60 sec
Only tried with Darktable versions since 4.2.
My Piwigo Apache server lists minimal logs:
192.168.64.1 - - [02/Aug/2023:15:33:25 -0700] “POST /piwigo/ws.php?format=json HTTP/1.1” 200 27
192.168.64.1 - - [02/Aug/2023:15:33:25 -0700] “POST /piwigo/ws.php?format=json HTTP/1.1” 200 390
192.168.64.1 - - [02/Aug/2023:15:33:44 -0700] “POST /piwigo/ws.php?format=json HTTP/1.1” 200 53
192.168.64.1 - - [02/Aug/2023:15:33:44 -0700] “POST /piwigo/ws.php?format=json HTTP/1.1” 200 88
192.168.64.1 - - [02/Aug/2023:15:33:44 -0700] “POST /piwigo/ws.php?format=json HTTP/1.1” 401 51
192.168.64.1 - - [02/Aug/2023:15:33:44 -0700] “POST /piwigo/ws.php?format=json HTTP/1.1” 200 5867

uploading from a web page gives different Apache log info:
192.168.64.1 - - [02/Aug/2023:15:48:33 -0700] “POST /piwigo/ws.php?method=pwg.images.upload&format=json HTTP/1.1” 200 45
192.168.64.1 - - [02/Aug/2023:15:48:33 -0700] “GET /piwigo/i.php?/upload/2023/08/02/20230802154833-a4c45fd6-me.jpg HTTP/1.1” 200 93808
192.168.64.1 - - [02/Aug/2023:15:48:33 -0700] “POST /piwigo/ws.php?method=pwg.images.upload&format=json HTTP/1.1” 200 224
192.168.64.1 - - [02/Aug/2023:15:48:34 -0700] “POST /piwigo/ws.php?format=json&method=pwg.images.uploadCompleted HTTP/1.1” 200 145
192.168.64.1 - - [02/Aug/2023:15:48:34 -0700] “GET /piwigo/i.php?/upload/2023/08/02/20230802154833-a4c45fd6-sq.jpg HTTP/1.1” 200 9082
192.168.64.1 - - [02/Aug/2023:15:48:37 -0700] “GET /piwigo/ HTTP/1.1” 200 3626

Any ideas?

Try without a dash in the filename.

The example with dash, “upload/2023/08/02/20230802154833-a4c45fd6-me.jpg”, was automatically generated and works. That log example was web page copy to Piwigo using jpgs. Direct copy from RAWs in Darktable fail.