What's wrong with my NFS setup?

I had previously been able to configure an NFS server on a computer running CentOS 6.6, and to mount the file system in a Virtual Machine with the same OS and using autofs.

Last week I did a fresh install of all the OSs I had, and now for some reason I cannot get it to work. The server computer still runs CentOS 6.6, and the Virtual Machine is now running CentOS 7 (I also tried it with another Virtual Machine running Debian Wheezy, but it still didn't work).

The server (centosserv) is running on 192.168.1.89, and the client (centoscli, the CentOS 7 one) on 192.168.1.100.

The file system I want to share is /NFSSHARE and /NFSSHARE/mydir, and as such the /etc/exports file on the server contains the following:

/NFSSHARE       192.168.1.100(fsid=0,rw,sync,no_subtree_check,root_squash,anonuid=1000,anongid=1000)
/NFSSHARE/mydir 192.168.1.100(ro,sync,no_subtree_check)

If I run showmount -e I get this:

[root@centosserv ~]# showmount -e
Export list for centosserv:
/NFSSHARE/mydir 192.168.1.100
/NFSSHARE       192.168.1.100

So everything looks good so far.

On the client side, I edited the /etc/auto.master to include the following line:

/mnt/nfs       /etc/auto.nfs-share       --timeout=90

And then created the /etc/auto.nfs-share file with the following contents:

[root@centoscli ~]# cat /etc/auto.nfs-share
writeable_share        -rw 192.168.1.89:/
non_writeable_share    -ro 192.168.1.89:/mydir

This also seems to be working, given the below output:

[root@centoscli ~]# mount | grep nfs-share
/etc/auto.nfs-share on /mnt/nfs type autofs (rw,relatime,fd=18,pgrp=2401,timeout=90,minproto=5,maxproto=5,indirect)

At this point, /mnt/nfs/writeable_share and /mnt/nfs/non_writeable_share are not mounted, unless I try to access them directly, as per this tutorial (which is the same I had followed the last time I set up the NFS server*). So only after I tried ls -l /mnt/nfs/writeable_share should it be mounted. But the output I get is:

[root@centoscli ~]# ls -l /mnt/nfs/writeable_share
ls: cannot access /mnt/nfs/writeable_share: No such file or directory

I pinged the server from the client and vice versa, just to check that they could both reach each other, and they seem to do.

I did everything exactly the same way I had done the first time round, yet for some reason I cannot get it to work this time. I have tried doing this by editing the /etc/fstab file on the client side instead of using autofs, but it doesn't seem to work that way either.

What else can I check, or where I have gone wrong?

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*With the exception of the first three steps, since I have neither a service called nfs-common neither a /etc/default/nfs-common file.

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EDIT

I was checking out this tutorial on a CentOS group on FB that, after the server side is supposedly settled and we're ready to start configuring the client side, says this:

Test if you can see NFS server:

showmount -e

So I'm guessing that using showmount -e on the client I should be able to get some info on the server, or it at least some acknowledgement that I can mount file systems from that server on this client. However, I tried using showmount -e on the client side, and the only message I got was this:

 clnt_create: RPC: Program not registered

I'm guessing this could be the problem, but I'm not sure what it means.