Windows ODBC connection trouble? ISP issue?

I have set up a pg database server for my organization on a cloud server using PG 8.2;

I am trying to provide connections to the db for some members using MS Access.  I developed a small MS Access application using Windows ODBC – it works fine from my house. 

I have this line in pg_hba.conf:

Host    all    mydbuserID    0.0.0.0/0     password

BUT… I cannot re-create the ODBC connection in our organization’s offices!   

I have de-bugged by taking my laptop to the office – it will not connect  to the db there – but is ok at my house.

(I have also checked 2 other locations with public wi-fi; could not connect from either of them)

This seems to be related to the ISP blocking data – I have ruled out the router in the office.

Is this a common SNAFU to encounter? 

I spent an hour on the phone with tech support for the office’s ISP;  the guy insisted it could not be a problem on their side!

Is there something I could be overlooking?

Any help or guidance would be greatly appreciated.

Regards,

JPD