domino Nsf files are failing

Domino nsf files are failing while taking the full and incremental backups due to the below error/

2018-07-16 23:57:10 avlotus Error <40281>: elemtype - NSFDbOpen failed for file: /fxsplnm002//system/fdfxlnma01/maillz/w/wan33041.nsf This database is currently in use by another person or process, and cannot be accessed at this time. In order to share a Notes database, it must be accessed via a Domino Server by all users of the database. (Log #1)

2018-07-16 23:57:13 avlotus Error <40281>: elemtype - NSFDbOpen failed for file: /fxsplnm002//system/fdfxlnma01/maillz/w/wan10880.nsf This database is currently in use by another person or process, and cannot be accessed at this time. In order to share a Notes database, it must be accessed via a Domino Server by all users of the database. (Log #1)