GL-AX1800 Flint Dyndns in Luci always fails

i have the GL-AX1800 Flint and i cannot get dyndns for no-ip to work, it always gives me the same error, that there is no script/url specified.
The Firmware Version is 4.2.1, i have installed all the dyndns packages in Luci.
I already searched online for this, and on the openwrt github there is exactly such an issue, but i dont seem to be able to get this to work like they suggest.

Here is the link for the openwrt bug

Apparently the fix is in newer versions of openwrt?
Does anyone have an idea how to do this?
i would really appreciate your help!