SAMBA CIFS: Authentication for user [XXXXXXX] has FAILED

Hi, when i was browsing log on my mycloud2ex2 ultra i found this:
2019 Nov 2 15:51:12 SAMBA CIFS: Authentication for user [xxxxxx] has FAILED.
2019 Nov 2 12:22:47 SAMBA CIFS: Authentication for user [xxxxxx] has FAILED.

xxxxxx is @ I wrote on first start of the device.

How to fix this ?