Unable to change backup location in Vcenter VAMI and fails with an error - "General system error reported by backup server" when using SMB protocol

Products

• VMware vCenter Server

Issue/Introduction

While changing the backup server in VAMI, we encountered the following error: "General system error reported by backup server"

In the applmgmt.log, we observed this error:

YYYY-MM-DDTHH:MM:SS PM UTC [8341] ERROR: plugins.SMBClientStorageIOLib: Command failed with error: NT_STATUS_IO_TIMEOUT

$ less applmgmt.log.* | grep NT_STATUS
YYYY-MM-DDTHH:MM:SS AM UTC [11707]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to xx.xx.xx.xx failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11707]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <backupserver> (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11707]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <backupserver> failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11707]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <backupserver> failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11718]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to xx.xx.xx.xx failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11718]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to xx.xx.xx.xx failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11718]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to xx.xx.xx.xx failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11718]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <backupserver> failed (Error NT_STATUS_IO_TIMEOUT)
YYYY-MM-DDTHH:MM:SS AM UTC [11718]ERROR:plugins.SMBClientStorageIOLib:smb cmd failed. RC: 1, Err: do_connect: Connection to <backupserver> failed (Error NT_STATUS_IO_TIMEOUT)

Few SMB protocol verification commands:

/usr/bin/smbclient -d 10 //<backup server ip or fqdn>/<share location>/ -U <user> --send-buffer 100M -c "ls"

/usr/bin/smbclient -d 10 //<backup server ip or fqdn>/<share location>/ -U <user> -c "ls"

Running the below command shows the below error:

/usr/bin/smbclient //<backup-server>/<share> -U <user> -m SMB3 --option="client min protocol=SMB2" --option="client max protocol=SMB3" -c "ls"

>>>>do_connect: Connection to vcenter.server.com failed (Error NT_STATUS_IO_TIMEOUT)

Based on the nc-zv results the port 445 is not opened between the non-working vc and backup server
  
root@vcenter[ ~ ]# nc -zv <backupserver_IP> 445
<backupserver_FQDN [xx.xx.xx.xx] 445 (microsoft-ds): Connection timed out

 

Environment

vCenter server 7.x

vCenter server 8.x

Cause

SMB communication over port 445 is blocked at the network level between the backup server and vCenter.

Resolution

Engage your Network Team to resolve the issue related to the blocking of port 445.

 

Additional Information

If necessary, perform a network packet capture to gain a better understanding of the issue.