Why NFS share fails to mount when exported via IP/Hostname, but works with wildcard(*) exports?

Issue

• Why NFS share can't be mounted when exported via IP/Hostname, but works with wildcard(*) exports?
• How to mount share when NFS server and client are in different network?
• Mounting of NFS filesystem/share failed with below error:

[root@client ~]# mount -t nfs server:/new_share /mnt1 -vvv
mount.nfs: timeout set for Thu Jan 26 06:27:42 2023
mount.nfs: trying text-based options 'mountvers=3,addr=172.x.y.z'
mount.nfs: prog 100003, trying vers=3, prot=6
mount.nfs: trying 172.x.y.z prog 100003 vers 3 prot TCP port 2049
mount.nfs: prog 100005, trying vers=3, prot=17
mount.nfs: trying 172.x.y.z prog 100005 vers 3 prot UDP port 50036
mount.nfs: mount(2): Permission denied
mount.nfs: access denied by server while mounting server:/new_share