Android Agora Token/key issue : it work sometimes and sometime it show black screen

Question

Web Agora.io DYNAMIC_KEY_EXPIRED

id follow this link for token time expired issue, it worked at that time but again it showing black screen. it attached my token generation code of C# here,

            uint expireTime = 86400;
            //uint currentTime = (uint)Math.Floor((double)DateTime.Now.Ticks / 1000);
            uint currentTime = (uint)Math.Floor((double)indianTime.ToUniversalTime().Ticks / 1000);

            uint privilegeExpireTime = currentTime + expireTime;
            AccessToken token = new AccessToken(_appId, _appCertificate, _channelName, "0");
            token.addPrivilege(Privileges.kJoinChannel, privilegeExpireTime);
            token.addPrivilege(Privileges.kPublishAudioStream, privilegeExpireTime);
            token.addPrivilege(Privileges.kPublishVideoStream, privilegeExpireTime);
            string aToken = token.build();