Service Discovery fails with "failed to fetch state [500]: INTERNAL SERVER ERROR. Retrying in 1 second"

[BH2005 (Bernd Holzhauer)]

Yes sounds like exactly same issue:

Error when rescan devices

Root cause: werkzeug 3.1.0 breaking change (released October 31, 2024) werkzeug 3.1.0 was released on October 31, 2024 and introduced two new hard limits on form data parsing as potentially breaking changes. GitHub The two relevant changes: Request.max_form_memory_size now defaults to 500 kB instead of unlimited. Non-file form fields exceeding this size will raise a RequestEntityTooLarge error. GitHub max_form_parts stops reading request data if more than 1,000 parts are sent in multipart fo…

Workaround

Edit /omd/sites/<site>/lib/python3.12/site-packages/werkzeug/wrappers/request.py and raise the limits:

max_form_memory_size = 2_000_000   # 2 MB instead of 500 kB try what is working for you
max_form_parts = 10000             # instead of 1000

Greetz Bernd