You must make sure that the directory is exported and is accessible. From your post, what I understand is that you are using Clustered Data ONTAP.
How did you configure the NFS exports? via CLI or system manager?
If using NFS v3, no need to specify username and password there. NFS v3 basically allows access to exported resources based on clent IP addresses, not usernames. So, you should check the export policies of the SVM's root volume as well as the NFS exported directory to make sure that your windows system has sufficient permissions to access the exports. The following commands would give us some clue.
volume show ( for both SVM root and the Data Volumes)
export policy rule show ( for the relevant export policies)
From the client side, "showmount -e servername" and "rpcinfo -p servername" are some useful commands, if it was a linux client. Not sure if windows has any such commands available.
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