admin-ajax.php JSON parsing problem

Hi,

I just installed WordPress on Debian 12 and got a problem with admin-php which show up when I try to create a new blog post and try to upload a photo. The photo is in the uploads folder, but the media gallery is not shown, instead I only get a spinner (forever).

The error message is: JSON.parse: unexpected character at line 1 column 1 of the JSON data

The request is: {“success”:true,”data”:[{“id”:56,”title”:”OLYMPUS DIGITAL CAMERA”,”filename”:”P1011495-3.jpg”,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-3.jpg”,”link”:”https:\/\/www.lichtgezaubert.de\/?attachment_id=56″,”alt”:””,”author”:”1″,”description”:””,”caption”:”OLYMPUS DIGITAL CAMERA”,”name”:”olympus-digital-camera-6″,”status”:”inherit”,”uploadedTo”:39,”date”:1723821857000,”modified”:1723821857000,”menuOrder”:0,”mime”:”image\/jpeg”,”type”:”image”,”subtype”:”jpeg”,”icon”:”https:\/\/www.lichtgezaubert.de\/wp-includes\/images\/media\/default.png”,”dateFormatted”:”16. August 2024″,”nonces”:{“update”:”645a324215″,”delete”:”94394a6ac2″,”edit”:”1e85034043″},”editLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=56&action=edit”,”meta”:false,”authorName”:”michael”,”authorLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/profile.php”,”uploadedToTitle”:”Gro\u00dfer Ahornboden”,”uploadedToLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=39&action=edit”,”filesizeInBytes”:69729,”filesizeHumanReadable”:”68 kB”,”context”:””,”height”:675,”width”:900,”orientation”:”landscape”,”sizes”:{“thumbnail”:{“height”:150,”width”:150,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-3-150×150.jpg”,”orientation”:”landscape”},”medium”:{“height”:225,”width”:300,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-3-300×225.jpg”,”orientation”:”landscape”},”full”:{“url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-3.jpg”,”height”:675,”width”:900,”orientation”:”landscape”}},”compat”:{“item”:””,”meta”:””}},{“id”:44,”title”:”OLYMPUS DIGITAL CAMERA”,”filename”:”P1011495-2.jpg”,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2.jpg”,”link”:”https:\/\/www.lichtgezaubert.de\/?attachment_id=44″,”alt”:””,”author”:”1″,”description”:””,”caption”:”OLYMPUS DIGITAL CAMERA”,”name”:”olympus-digital-camera-5″,”status”:”inherit”,”uploadedTo”:39,”date”:1723819536000,”modified”:1723819536000,”menuOrder”:0,”mime”:”image\/jpeg”,”type”:”image”,”subtype”:”jpeg”,”icon”:”https:\/\/www.lichtgezaubert.de\/wp-includes\/images\/media\/default.png”,”dateFormatted”:”16. August 2024″,”nonces”:{“update”:”c6d015f9ad”,”delete”:”42f16b7567″,”edit”:”cb70b3dcff”},”editLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=44&action=edit”,”meta”:false,”authorName”:”michael”,”authorLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/profile.php”,”uploadedToTitle”:”Gro\u00dfer Ahornboden”,”uploadedToLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=39&action=edit”,”filesizeInBytes”:69729,”filesizeHumanReadable”:”68 kB”,”context”:””,”height”:675,”width”:900,”orientation”:”landscape”,”sizes”:{“thumbnail”:{“height”:150,”width”:150,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-150×150.jpg”,”orientation”:”landscape”},”medium”:{“height”:225,”width”:300,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-300×225.jpg”,”orientation”:”landscape”},”full”:{“url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2.jpg”,”height”:675,”width”:900,”orientation”:”landscape”}},”compat”:{“item”:””,”meta”:””}},{“id”:43,”title”:”OLYMPUS DIGITAL CAMERA”,”filename”:”P1011495-2-3.jpg”,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-3.jpg”,”link”:”https:\/\/www.lichtgezaubert.de\/?attachment_id=43″,”alt”:””,”author”:”1″,”description”:””,”caption”:”OLYMPUS DIGITAL CAMERA”,”name”:”olympus-digital-camera-4″,”status”:”inherit”,”uploadedTo”:39,”date”:1723819467000,”modified”:1723819467000,”menuOrder”:0,”mime”:”image\/jpeg”,”type”:”image”,”subtype”:”jpeg”,”icon”:”https:\/\/www.lichtgezaubert.de\/wp-includes\/images\/media\/default.png”,”dateFormatted”:”16. August 2024″,”nonces”:{“update”:”b501f266d2″,”delete”:”3926a8ff65″,”edit”:”0072e64933″},”editLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=43&action=edit”,”meta”:false,”authorName”:”michael”,”authorLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/profile.php”,”uploadedToTitle”:”Gro\u00dfer Ahornboden”,”uploadedToLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=39&action=edit”,”filesizeInBytes”:69729,”filesizeHumanReadable”:”68 kB”,”context”:””,”height”:675,”width”:900,”orientation”:”landscape”,”sizes”:{“thumbnail”:{“height”:150,”width”:150,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-3-150×150.jpg”,”orientation”:”landscape”},”medium”:{“height”:225,”width”:300,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-3-300×225.jpg”,”orientation”:”landscape”},”full”:{“url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-3.jpg”,”height”:675,”width”:900,”orientation”:”landscape”}},”compat”:{“item”:””,”meta”:””}},{“id”:42,”title”:”OLYMPUS DIGITAL CAMERA”,”filename”:”P1011495-2-2.jpg”,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-2.jpg”,”link”:”https:\/\/www.lichtgezaubert.de\/?attachment_id=42″,”alt”:””,”author”:”1″,”description”:””,”caption”:”OLYMPUS DIGITAL CAMERA”,”name”:”olympus-digital-camera-3″,”status”:”inherit”,”uploadedTo”:39,”date”:1723819418000,”modified”:1723819418000,”menuOrder”:0,”mime”:”image\/jpeg”,”type”:”image”,”subtype”:”jpeg”,”icon”:”https:\/\/www.lichtgezaubert.de\/wp-includes\/images\/media\/default.png”,”dateFormatted”:”16. August 2024″,”nonces”:{“update”:”7dc61e2d64″,”delete”:”07b0212b98″,”edit”:”b90bacbb9c”},”editLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=42&action=edit”,”meta”:false,”authorName”:”michael”,”authorLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/profile.php”,”uploadedToTitle”:”Gro\u00dfer Ahornboden”,”uploadedToLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=39&action=edit”,”filesizeInBytes”:69729,”filesizeHumanReadable”:”68 kB”,”context”:””,”height”:675,”width”:900,”orientation”:”landscape”,”sizes”:{“thumbnail”:{“height”:150,”width”:150,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-2-150×150.jpg”,”orientation”:”landscape”},”medium”:{“height”:225,”width”:300,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-2-300×225.jpg”,”orientation”:”landscape”},”full”:{“url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-2.jpg”,”height”:675,”width”:900,”orientation”:”landscape”}},”compat”:{“item”:””,”meta”:””}},{“id”:41,”title”:”OLYMPUS DIGITAL CAMERA”,”filename”:”P1011495-2-1.jpg”,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-1.jpg”,”link”:”https:\/\/www.lichtgezaubert.de\/?attachment_id=41″,”alt”:””,”author”:”1″,”description”:””,”caption”:”OLYMPUS DIGITAL CAMERA”,”name”:”olympus-digital-camera-2″,”status”:”inherit”,”uploadedTo”:39,”date”:1723817794000,”modified”:1723817794000,”menuOrder”:0,”mime”:”image\/jpeg”,”type”:”image”,”subtype”:”jpeg”,”icon”:”https:\/\/www.lichtgezaubert.de\/wp-includes\/images\/media\/default.png”,”dateFormatted”:”16. August 2024″,”nonces”:{“update”:”755992719f”,”delete”:”c2c7312f02″,”edit”:”a5ecc6a971″},”editLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=41&action=edit”,”meta”:false,”authorName”:”michael”,”authorLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/profile.php”,”uploadedToTitle”:”Gro\u00dfer Ahornboden”,”uploadedToLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=39&action=edit”,”filesizeInBytes”:69729,”filesizeHumanReadable”:”68 kB”,”context”:””,”height”:675,”width”:900,”orientation”:”landscape”,”sizes”:{“thumbnail”:{“height”:150,”width”:150,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-1-150×150.jpg”,”orientation”:”landscape”},”medium”:{“height”:225,”width”:300,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-1-300×225.jpg”,”orientation”:”landscape”},”full”:{“url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-1.jpg”,”height”:675,”width”:900,”orientation”:”landscape”}},”compat”:{“item”:””,”meta”:””}},{“id”:40,”title”:”OLYMPUS DIGITAL CAMERA”,”filename”:”P1011495-2.jpg”,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2.jpg”,”link”:”https:\/\/www.lichtgezaubert.de\/?attachment_id=40″,”alt”:””,”author”:”1″,”description”:””,”caption”:”OLYMPUS DIGITAL CAMERA”,”name”:”olympus-digital-camera”,”status”:”inherit”,”uploadedTo”:39,”date”:1723817701000,”modified”:1723817701000,”menuOrder”:0,”mime”:”image\/jpeg”,”type”:”image”,”subtype”:”jpeg”,”icon”:”https:\/\/www.lichtgezaubert.de\/wp-includes\/images\/media\/default.png”,”dateFormatted”:”16. August 2024″,”nonces”:{“update”:”a83e4d391a”,”delete”:”64b24834bc”,”edit”:”490e86f8fb”},”editLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=40&action=edit”,”meta”:false,”authorName”:”michael”,”authorLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/profile.php”,”uploadedToTitle”:”Gro\u00dfer Ahornboden”,”uploadedToLink”:”https:\/\/www.lichtgezaubert.de\/wp-admin\/post.php?post=39&action=edit”,”filesizeInBytes”:69729,”filesizeHumanReadable”:”68 kB”,”context”:””,”height”:675,”width”:900,”orientation”:”landscape”,”sizes”:{“thumbnail”:{“height”:150,”width”:150,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-150×150.jpg”,”orientation”:”landscape”},”medium”:{“height”:225,”width”:300,”url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2-300×225.jpg”,”orientation”:”landscape”},”full”:{“url”:”https:\/\/www.lichtgezaubert.de\/wp-content\/uploads\/2024\/08\/P1011495-2.jpg”,”height”:675,”width”:900,”orientation”:”landscape”}},”compat”:{“item”:””,”meta”:””}}]}

I tried several online JSON parser (https://json.parser.online.fr/ and https://jsonformatter.org/json-parser) and they say the JSON is ok (I also cannot see something wrong)

The HTTP headers are:

Cache-Control no-cache, must-revalidate, max-age=0
Connection Keep-Alive
Content-Type application/json; charset=UTF-8
Date Sat, 17 Aug 2024 12:27:01 GMT
Expires Wed, 11 Jan 1984 05:00:00 GMT
Keep-Alive timeout=5, max=100
Referrer-Policy strict-origin-when-cross-origin
Server Apache/2.4.57 (Debian)
Transfer-Encoding chunked
X-Content-Type-Options nosniff
X-Frame-Options SAMEORIGIN
X-Robots-Tag noindex
X-WP-Total 6
X-WP-TotalPages 1

The script that is causing the problem is admin-ajax.php

When I try to open an image (e.g. https://www.lichtgezaubert.de/wp-content/uploads/2024/08/P1011495-3.jpg) everything seems fine.

What can I do to debug / solve this?

Best regards, Michael

The page I need help with: [log in to see the link]