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Library Technology Support: Common database errors

To keep clients up-to-date concerning developments related to library e-resources, systems, databases and applications.

Certificate error when accessing electronic resources

When accessing the Unisa Library’s e-resources or e-reserves & recommended books, you will be stopped by different error messages, such as: your connection is not secure; your connection is not private; problems associated with the website's security certificate; or untrusted connection. See screen captures below. ​                                                                                                                                                                                                                                                          

This is due to the fact that our current electronic resources security certificate has expired. We are awaiting the purchase and upgrade of a new certificate.

For the time being, please proceed as follows, depending on the browser you are using:


  • For Internet Explorer: 

            Click on "Continue to this website (not recommended)”.




  • For Google Chrome: 

Click on “Advanced”,

then click on “Proceed to ___”.

For example,

“Proceed to (unsafe)” for e-reserves & recommended books;


"Proceed to (unsafe)” for other e-resources. 







  • For Firefox: 

Click on "Advanced",

then click on "Add Exception...",

and then click on "Confirm Security Exception".










Although the messages do not recommend this action, there is no danger in continuing to the website since these are trusted sources.                                                      

Taylor & Francis

Client IP blocked

We have applied usage limits to our databases in order to comply with some vendor restrictions. This means that when accessing Taylor & Francis, sometimes you may get the following error:


This problem occurs when there is excessive usage of the database via the Unisa account. Examples of such include:

  • A single user or a single IP address downloads a specific title more than 10 times.
  • Large number of simultaneous users and high usage of Taylor and Francis Online Journals at a given time.

Please refrain from:

  • Sharing your login details with others,
  • Failing to log off when using public workstations to access databases,
  • Excessive downloading of full text content.  
If you get the above error message, email us at:




502 Bad Gateway / "502 Proxy Error"

Sometimes, when accessing online resources you might receive a 502 Bad Gateway/ 502 Proxy Error message. This occurs when the Web Access Management (WAM) proxy server “falls over” due to technical problems on the Unisa network or when an individual’s server received an invalid response from another server. 


If you get this error, email us at and we will restart the relevant servers.



Sometimes when using EBSCOHOST databases you may get the following error:


"A System Problem has Occurred. To begin a new session, please login again."

You may also receive this error message because you used your browser's back button rather than the navigation available within the EBSCOHOST interface.

This is a problem on EBSCO's end. They are working on the problem and recommend the following:

1.     Clear your temporary Internet files, cache and browser history.

2.     Restart your browser and login through the library website again.

This problem mostly happens with Internet Explorer and Safari, so it might be better to also download Firefox ( or Google Chrome (


E-Books links

Sometimes when you click on a specific link from the Library Catalogue (WebPac) to open an e-book title, you might encounter various errors.





If you receive any of these error messages, please email us with the details at: