Can't use namecheap DDNS

i switched from no-ip to namecheap. can’t get namecheap working
i use as username bot my hostname and my username
and the password provided by namecheap

Troubleshooting requires checking the logs. Update the connection with namecheap and check the logs:

Logs/system Logs/Dynamic DNS

16:01:29 ddns[2202]: Dynamic DNS update for nextcloud.aivallecrosia.com (Namecheap) failed:
16:01:29 ddns[2202]: DDNSAuthenticationError: Authentication against the server has failed
16:01:41 ddns[2268]: An update has not been performed because earlier updates failed for nextcloud.aivallecrosia.com
16:01:41 ddns[2268]: Last failure message:
16:01:41 ddns[2268]: DDNSAuthenticationError: Authentication against the server has failed
16:01:41 ddns[2268]: Further updates will be withheld until 2020-10-02 02:01:29.005412
16:05:01 ddns[3299]: An update has not been performed because earlier updates failed for nextcloud.aivallecrosia.com
16:05:01 ddns[3299]: Last failure message:

after some hours it seems to be correctly connected