SAP ASE Backup issue with NFS mount. write access Error

Hi , I am taking backup through SAP ASE DB Application using dump command.
I am taking the backup on NFS mount.
But it is giving me below errors. please help in this case. We are qualifying SAP-ASE for our customers
1> dump database test_DB to '/mnt1_nfs/sapase-stu/1.bak'

2> go

Backup Server: 4.172.1.4: The value of 'allocated pages threshold' has been set

to 40%.

Backup Server session id is: 6. Use this value when executing the

'sp_volchanged' system stored procedure after fulfilling any volume change

request from the Backup Server.

Backup Server: 4.41.1.1: Creating new disk file /mnt1_nfs/sapase-stu/1.bak.

Backup Server: 4.141.2.87: [11] The 'lockf' call failed for database/archive

device while working on stripe device '/mnt1_nfs/sapase-stu/1.bak' with error

number 5 (Input/output error). Refer to your operating system documentation for

further details.

Backup Server: 6.53.1.1: OPERATOR: Volume on device '/mnt1_nfs/sapase-stu/1.bak'

cannot be opened for write access. Mount another volume.