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Hubble Space Telescope
Test for Communication Problems with APT

Please try these steps to test for and resolve communication problems with APT:

  1. Install and start APT
  2. Test access to documentation

    Click on the "Help" menu and select "Phase I Call for Proposals".

    1. If it worked you will see the Call for Proposals document pop up in a separate window. Go on to step 3.
    2. If it didn't work you will get a message like:

      Please check network status

      If you are in fact connected to the internet, you may need to set an HTTP proxy:

      Go to the "Edit" menu (or "APT" menu on Mac), click on "Preferences", select the "Network" tab and enter your HTTP proxy host and port. (Your system manager should be able to supply you with these values. You may also be able to find them in the preferences for your web browser.)

      Quit APT and start it up again.

      Now try the test again. If you still can't connect there may be a problem with the proxy information you put in; please double check. If it still doesn't work, please send e-mail to

  3. Test access to investigator database

    Click on the "New Document" button and choose "New HST Proposal". Then click on the "New Co-I" button. Type in a name like "peter" and hit return.

    1. If it worked you will get a pop up that gives numerous people whose first or last name begins with "peter". You should now be set up to use APT without any communication problems
    2. If the connection to the server cannot be establish you will likely not be able to type into the Name Search box (and the word "Offline" will appear next to the Name Search box). Alternatively, if the connection was lost while you were typing into the Name Search box you might get a pop up message like:

      Unable to contact the STScI server

      If you are in fact connected to the internet then the server may actually down. But it is also possible that the communication port that APT needs (20210) is not open. To test from the command line:

      telnet 20210

      If port 20210 isn't open then you will see "Connection refused". Please talk to your sysadmin about opening port 20210 to, try a different network, or start APT from the command with a switch to our proxy on port 80 (which is usually open for HTTP traffic). Here are instructions:

      • On a MacOS: Navigate to the APT installation directory and then down into /bin:

        ./apt -P aptserver.port=80

      • On Linux: Navigate to the APT installation directory:

        ./APT -P aptserver.port=80

      • On Windows: Right click on the APT icon and select "Properties". In the field called "Target" you should see the path to the executable code. Add the command line argument after that:

         C:\Users\peterson\APT_27.1\APT.bat -P aptserver.port=80

      Now try step 3 again. If it doesn't work please send us e-mail at