Can we add nodes to clusters in couchbase 2.5.1?

I am trying to add a second couchbase 2.5.1 node to a couchbase 2.5.1 cluster that has one node currently in it. When I created the new node I first tried to add it to the existing cluster during configuration, but it gave me this error:
Attention - Prepare join failed. Authentication failed.
Verify username and password. Got HTTP status 401 from REST call post
to Body was: []

I then created it in a new cluster and tried to add it to the existing cluster from the admin console of the existing console by clicking ‘Add Server’ but I got the exact same error (and I made sure to specify the credentials for the new cluster I had just created when trying to add). I came across this bug report while searching up the original problem:

Does this mean I can’t create a cluster with couchbase 2.5.1 nodes?

Hi, not sure how to delete this topic so I’ll just post the issue and solution here:
I was setting up this new node inside of a windows Azure cloud service which only contains the existing couchbase node that I’m trying to connect to, and the new node I just created. I didn’t check the internal IP address of this new node properly though, and so the IP I had on the config screen for it didn’t match the actual internal IP address. Once I fixed the IP address I was able to connect the servers. I also uninstalled couchbase 2.5.1 and installed couchbase 3.0.2 on the new node instead, though I’m fairly certain the issue was with the IP addresses not matching.