I have both applications running, and followed the directions here.  I am able to add the DOORS project as a "Uses: Requirements" association from RQM.

However, when I go into DOORS to add RQM as a Remote Service, I can add the RQM server in the "Server List" section, but when I try to add a "Collaboration Link" I never get a list of RQM projects to choose from.  I get an HTTPS security warning, to which I reply "Yes."  Then I log in to RQM, and that's it.  Subsequent attempts simply result in a "flash" of the OAuth window in the background, and nothing populated in the "Collaboration Link" section.

I am on DOORS 9.5.0.1, and CLM 4.0.3.

Thanks, Gary