Problem when changing right access for NFS share (unity500)

Hello i cannot change access rights from "Read/Write, allow Root" to "Read-only, allow Root " : error code 0x6500158 as seen in message below :

Cannot connect to remote system, please check the status of remote system and try again later (Error Code:0x6500158)

The share is part of a replication session which is paused.

I d appreciate to have any help whith this issue.

Cheers