ConnectionUnavailable: Cannot open connection to ConnectionProfile('bolt://

I'm trying to connect to a Neo4j instance using py2neo in a Jupyter Notebook running on See the example here:

I'll get the following error:

ConnectionUnavailable: Cannot open connection to ConnectionProfile('bolt://...')

What causes this problem and how can I work around it?

Any more error info?

What kind of URL and server do you have?
Which py2neo version, which neo4j version.
Does it work in a regular python shell with py2neo?


Neo4j server:
Operating System: CentOS Linux 8 (Core)

Neo4j: Enterprise 4.1.1

py2neo: 2020.1.1

Our Neo4j instance is publicly accessible (see for details) here: (username: reader, password: demo)

An example Jupyter Notebook is here:

You can run this notebook on to reproduce the error:

The same notebook works fine when run locally or on the Pangeo server:

Could it be incompatible python version or network visibility?

I.e. can you reach the neo4j server from your mybinder instance? perhaps they block ports outside of http(s) range?

Yes, thanks, it must be a blocked port.