Steve,
Is your Moodle and LAMS server able to "see each other"? Are they on the same network? You can test this by pinging from one server to another one.
I believe one of your server might be on an internal (behind a NAT) network therefore LAMS won't be able to reach and get the user details it requires.
Given these issues, which you aren't the first one to have, I believe we need to revisit the integrations.
For one, simplify the configuration settings. So you would only need to set up a password on both sides and let the server exchange all the rest of the configuration details.
Two, the "User Information URL" if you are behind a NAT, it won't work at all. So pass users details on each request might be the other option. Is a bit tedious and might take a slight performance hit, but it shouldn't be that hard though.
As we are embarking on Moodle 2 integration, I'll take these into account and see if they can be implemented too.
Thanks,
Ernie
Posted by Ernie Ghiglione