Traccar Maps Tab: JSON Error After Recent Update?

[nottheend]

Has anyone experienced similar issues or know what might be causing this API response mismatch where the maps interface receives HTML instead of JSON data?

When I open the maps tab of the web interface of Traccar, I get a red error toast:

Unexpected token '<', "<!DOCTYPE "... is not valid JSON

A device is sending location data via the Traccar app.

Configuration:

• Domain: https://osmand.mydomain.com:5055
• OsmAnd Domain configured in Cloudron backend location tab with port 5055
• Firewall port 5055 is open

Timeline:
The system was working until approximately 5 days ago when it stopped functioning. The issue appeared around June 13th, one day before the June 14th, 2025 Cloudron release (Changelog: "fix OpenID login from mobile apps"). Could this release be related to the problem?

Log entries:

2025-06-18 08:38:11 INFO: [Tbf925eb7: osmand < 173.244.42.173] GET / HTTP/1.1\r\nHost: nottheend.info\r\nUser-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/137.0.0.0 Safari/537.36\r\nAccept-Encoding: gzip\r\n\r\n
Jun 18 10:38:11 2025-06-18 08:38:11 INFO: [Tbf925eb7: osmand > 173.244.42.173] HTTP/1.1 400 Bad Request\r\ncontent-length: 0\r\n\r\n
Jun 18 10:38:11 2025-06-18 08:38:11 INFO: [Tbf925eb7] connected
Jun 18 10:38:12 2025-06-18 08:38:12 INFO: [Tbf925eb7: osmand < 173.244.42.173] GET /favicon.ico HTTP/1.1\r\nHost: mydomain.com\r\nUser-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/136.0.0.0 Safari/537.36\r\nAccept-Encoding: gzip\r\n\r\n
Jun 18 10:38:12 2025-06-18 08:38:12 INFO: [Tbf925eb7: osmand > 173.244.42.173] HTTP/1.1 400 Bad Request\r\ncontent-length: 0\r\n\r\n
Jun 18 10:38:16 2025-06-18 08:38:16 INFO: [Tbf925eb7] disconnected

The error suggests the maps interface is receiving HTML (DOCTYPE declaration) when expecting JSON data.

[james]

Hello @nottheend
I could not reproduce this issue with a fresh install and also not with the upgraded historic version from multiple versions back before the OpenID changes.

Do I understand you correctly that this error are only existent when using your browser? If so, can you try a different browser? From the Browser Agent in the log I can assume you are using a Chromium based browser on Linux, maybe try FireFox for testing.

Is the core functionality of tracking effected in any way?

[nottheend]

Thank you for the response and test.
I changed the identifier in the client and added it on the server. Also removed the device with the old identifier. The error is gone. Really surprising for me.

Still having the issue that no device is showing. Tried few things, like changing the port, domain, and checked the firewall.

For the sake of this threat, can be closed I guess, since it seems to be a conffig error.

[james]

Hello @nottheend
Just a fyi: in the traccar app on android or iOS you have to use the https://sub.DOMAIN.TLD of the traccar server.
No Port, No HTTP, it has to be https:// and the domain without a port`

[nottheend]

Thanks for the hint. I actually did that, but still not working: I still see all devices as offline.

And your assumption was correct regarding the browser: For a chromium browser, I got the Doctype error also for a completely fresh installation without any devices. In e.g. Edge I didn't face this issue

[james]

In the traccar app on android and iOS you can send the location manually.
Since it sends locations based on the intevall set in the app it could take multiple minutes before the first one is send.

Also, there is a display status button which show logs.
Can you download these logs and provide them here so I can take a look?