Impossible to download sftp from switch

[alcomint]

Hi,
I am trying to configure Alcatel lucent 6450-48 switch for zero-touch. When I am trying to download following file:
1) - e8e732754000.cfg --- configuration file
2) - e8e732754000.srt --- Script file

Then I am having permission denied, this setting was working file until a day before
Kindly help me:


THU JUN 09 13:32:14 : CLI (67) info message:
+++ [CLISHELL 6] Connection closed by remote host!
Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).

THU JUN 09 13:32:14 : SSH (109) error message:
+++ [SSH 64] Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
+++ [SSH 64] Couldn't initialise connection to server

THU JUN 09 13:32:15 : TELNET (80) info message:
+++ Session 6, Session Ending

THU JUN 09 13:32:15 : REMOTE_CONFIG (125) error message:
+++ File Download failed via SFTP

THU JUN 09 13:32:15 : REMOTE_CONFIG (125) info message:
+++ Download of Script file from Primary Server Failed
+++ Starting download of Script file: e8e732754000.srt from Secondary Server

THU JUN 09 13:32:15 : REMOTE_CONFIG (125) error message: