INWX Plugin not working

Describe the bug
I'm getting this error message with the INWX plugin:
CommandError: Saving debug log to /tmp/letsencrypt-log/letsencrypt.log
Unsafe permissions on credentials configuration file: /etc/letsencrypt/credentials/credentials-8
Encountered exception during recovery: certbot.errors.PluginError: INWX login failed: ('There was a problem: Authentication error (Error code 2200)', {'code': 2200, 'msg': 'Authentication error', 'svTRID': '20250204-', 'runtime': 3.0283})
INWX login failed: ('There was a problem: Authentication error (Error code 2200)', {'code': 2200, 'msg': 'Authentication error', 'svTRID': '20250204-', 'runtime': 3.0275})
Ask for help or search for solutions at https://community.letsencrypt.org. See the logfile /tmp/letsencrypt-log/letsencrypt.log or re-run Certbot with -v for more details.

at /app/lib/utils.js:16:13
at ChildProcess.exithandler (node:child_process:430:5)
at ChildProcess.emit (node:events:518:28)
at maybeClose (node:internal/child_process:1104:16)
at Socket. (node:internal/child_process:456:11)
at Socket.emit (node:events:518:28)
at Pipe. (node:net:343:12)

More Info:
The directory /etc/letsencrypt/credentials is empty
The plugin's config file is stored in /opt/certbot/lib/python3.11/site-packages/etc/letsencrypt/inwx.cfg

The settings entered in the UI:
dns_inwx_url = https://api.domrobot.com/xmlrpc/
dns_inwx_username = MY_USERNAME
dns_inwx_password = MY_PASSWORD
dns_inwx_shared_secret = your_shared_secret optional

Nginx Proxy Manager Version
v2.12.2

To Reproduce
Steps to reproduce the behavior:

1. Go to 'SSL Certificates'
2. Click on 'Add SSL Certificate'
3. Enter 'Domain Names', 'Email Address for Let's Encrypt'
4. Check 'Use a DNS Challenge'
5. Select 'INWX' from the dropdown menu
6. Check 'I Agree to the LE ToS'
7. Click on 'Save'
8. The error message from above is displayed

Expected behavior
Authentication to not fail

Start by reviewing the INWX settings in the SSL certificate flow and the generated /opt/certbot/lib/python3.11/site-packages/etc/letsencrypt/inwx.cfg file, then inspect the error path at /app/lib/utils.js. Reproduce the INWX DNS challenge with the reported settings and determine whether the generated credentials are accepted; done means authentication succeeds without the PluginError.