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Blank White Page Displays for Enterprise Survey

Date Published: Nov 24,2020


CategoryPlanned First Fix Release:Learn 9.1, 3900.0.0 Release,SaaS - v3800.11.0; Product:Extensions; Version:Learn 9.1, 3900.0.0,Learn 9.1 Q4 2019 (3800.0.0),Learn 9.1 Q2 2017 (3200.0.0),Learn 9.1 Q4 2017 (3300.0.0),Learn 9.1 Q2 2018 (3400.0.0),Learn 9.1 Q4 2018 (3500.0.0),Learn 9.1 Q2 2019 (3700.0.0),Learn 9.1 Q4 2016 (3100.0.0-rel.107+401e,SaaS,Learn 9.1 Q4 2015 (9.1.201510.1171621),Learn 9.1 Q2 2016 (3000.1.0-rel.52+991d)
Article No.: 000057848
Product:
Blackboard Learn
Release:
9.1;SaaS
Service Pack(s):
Learn 9.1, 3900.0.0, Learn 9.1 Q4 2019 (3800.0.0), Learn 9.1 Q2 2017 (3200.0.0), Learn 9.1 Q4 2017 (3300.0.0), Learn 9.1 Q2 2018 (3400.0.0), Learn 9.1 Q4 2018 (3500.0.0), Learn 9.1 Q2 2019 (3700.0.0), Learn 9.1 Q4 2016 (3100.0.0-rel.107+401e, SaaS, Learn 9.1 Q4 2015 (9.1.201510.1171621), Learn 9.1 Q2 2016 (3000.1.0-rel.52+991d)
Description:
A blank page appears instead of the enterprise survey entry form.
Steps to Repeat:
  1. Log in as a System Administrator
  2. Go to System Admin > Courses
  3. Create a Course (ex. 'Test_Survey')
  4. Enroll or Create User(s) in the new Course
  5. Go to System Admin > Enterprise Surveys
  6. Create a Survey (ex. 'Test_Survey')
  7. Create a Response Period by selecting the new Course and choosing a Student 
  8. Deploy the Survey to send an email
  9. Click the link in the email to take the survey.
Expected Behavior:
The survey appears in the browser window.

Observed Behavior:
The browser window displays a blank, white page.

Symptoms:

Surveys cannot be taken because the window is empty.  Once this occurs, the survey will be blank indefinitely, for all users in the response period.

Cause:

When a survey response form is loaded for the first time, a cache file is created in the shared content folder.  If an HTTP Head request is made to a survey response endpoint, the cache file is totally empty.  This empty cache file is then sent to all browsers requesting the form for this response period.

Resolution/Workaround:

While there can be multiple causes of HEAD requests, they have been found to be associated with security software such as Microsoft Safelinks probing the links found in emails. To confirm this issue, look in the bb-access logs for lines showing HEAD requests to survey URL endpoints, such as:
 
nnn.nn.nn.nnn 127.0.0.1 connector-22 - [22/Apr/2020:09:42:03 -0500] "HEAD /webapps/enterpriseSurvey/execute/serveSurvey?&rId=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx HTTP/1.1" 200 - "-" "-" 150 -

Identify the source IP address (nn.nn.nn.nnn) of the request. If it is associated with an email provider, work with your email provider to whitelist URLs beginning with "blackboard.institution.edu/webapps/enterpriseSurvey/*" from the service then contact Blackboard Support for a workaround to remove the empty cache file.

Information:

If the cache file is deleted, but the HEAD requests are not stopped at the source, the issue will continue to occur.

Target Release:

Learn 9.1, 3900.0.0

SaaS - Fixed (v3800.11.0)

Patch Available:

No






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