Getting an error in the logs when registerring

System.FormatException: String '25/12/1989' was not recognized as a valid DateTime.
   at System.DateTime.Parse(String s)
   at SnitzCore.Service.MemberService.Create(Member member, List`1 additionalFields) in E:\GitHub\Snitz.NetCore\MVCForum.Service\MemberService.cs:line 160