Installation

renderProblem 404 Can't authenticate error

renderProblem 404 Can't authenticate error

by Gavin LaRose -
Number of replies: 5

With a clean 2.13 install, I'm getting the a javascript alert popup with the error "/webwork2/instructorXMLHandler: Forbidden" when I try to render a problem in the setDetail editor.

The server response (from the browser console or apache error log) is 

Error message for command: renderProblem
faultcode: 404
faultstring: WebworkWebservice: Can't authenticate -- session may have timed out.
Call stack
The information below can help locate the source of the problem.
 o in WeBWorK::ContentGenerator::instructorXMLHandler::content called at line 232 of .../webwork2/lib/WeBWorK/ContentGenerator.pm
 o in WeBWorK::ContentGenerator::go called at line 384 of .../webwork2/lib/WeBWorK.pm
Request information
  Method     Post
  URI        /webwork2/instructorXMLHandler
  UserAgent  [user agent string]

Further confusing details: this fails with the same error if I revert back to WeBWorK 2.12. However, on a second server running WeBWorK 2.12 with (insofar as I can tell) the same operating system and configuration, rendering works fine. I turned on $UNIT_TESTS_ON in WebworkClient.pm and instructorXMLHandler.pm, and insofar as I can tell the same data are being sent back and forth on both servers.

There is one minor difference in that the install date for the 2.12 system that doesn't work was August 2016, while that which works is April 2017. But I think the configuration is the same.

I have tracked down the version numbers of the Perl modules that seemed most likely to be at issue, and they all appear to be the same between the two servers.

Any thoughts about what is eliciting the error are very welcome.

Thanks,
Gavin

In reply to Gavin LaRose

Re: renderProblem 404 Can't authenticate error

by Michael Gage -
Likely this fails when you try to display the problems in the homework editor as well -- it uses the same mechanism.

See also:

In reply to Michael Gage

Re: renderProblem 404 Can't authenticate error

by Gavin LaRose -
Hi Mike,

It does fail elsewhere as well. My next test will be to pull WeBWorK 2.13 onto my development server and use the same configuration files there; if it still works on the development box, then it's either a subtle mismatch in Perl module versions between the two, or a driver issue due to differing hardware.

Gavin
In reply to Gavin LaRose

Re: renderProblem 404 Can't authenticate error

by Nathan Wallach -
I'm wondering if a server level and servername configuration issue could have been the cause or possibly a mix of http and https.


Adding an extra record to /etc/hosts to make sure the machine can resolve its own FQDN without use of DNS may help, or more careful review of the various hostname related settings in the WW config.
In reply to Gavin LaRose

Re: renderProblem 404 Can't authenticate error

by Michael Gage -
Gavin. Was this problem resolved? Do you remember the fix?
In reply to Michael Gage

Re: renderProblem 404 Can't authenticate error

by Andrew Parker -
I ran into a similar situation - caused by an inability to write to /opt/webwork/webwork2/tmp (specifically under selinux):

semanage fcontext -a -t httpd_sys_rw_content_t "/opt/webwork/webwork2/tmp(/.*)?"
(which will also need to be applied to htdocs, DATA, and logs, also in webwork2 directory)