Hi @aSilentSniper,
Thanks for mentioning my issue. I'll try your patch the next few days.

I've tried your patched version. Works like a charm. Thanks!

When pasting an empty, or wrong token, the check script crashes:

Traceback (most recent call last):
  File "/usr/local/bin/check_pihole.py", line 77, in <module>
    main()
  File "/usr/local/bin/check_pihole.py", line 64, in main
    if url_output["status"] != "enabled":
TypeError: list indices must be integers or slices, not str

Unfortunately, the Pihole API answers with a HTTP status code 200. So there's only checking for an empty result I think. Having my patch applied, the output is:

UNKNOWN: Empty result from Pihole. Wrong API token?

Maybe you wanna add this patch in this PR.
check_pihole.py.patch

(Apologies if this is not the best method for sharing the patch.)

@wopfel Thanks for your Patch it is working and i added it to this PR