Continue buttons disappearing

Hi,

Just dropping by as we have the exact same issue as well. (either no Continue button, or wouldn't let learner to go to the next chapter)

We are using SuccessFactors for our LMS, and uses Rise 360 for a large number of courses.

Our learners composed of office staff and frontline staff that are scattered at many remote sites. And a small fraction of those learners has this exact same issue. Since our learner's base is large to us, and we have a 1 man support team, it does occupy our support team quite a bit of time. 

There seems to be no specific pattern that we could spot so far. Chrome, Edge, Firefox, desktops, mobiles, tablets, connecting through our company network, connecting through direct internet line, all encountered this same issue. And it happens randomly, random learner, and at a random chapters. When we cancel the existing assignment (enrolment) and re-assign the course to the same learner, most of the time the issue will went away (but learner will have to re-start the course all over again and we end of just sending them an equivalent PowerPoint slide instead). 

At first we thought it was client side issue, may be a bad cache on learner's machine. But we kindly of ruled that out quickly, as that was the first time learner accessing the course, so it can't be it (right?). Now we are guessing would it be possible that there is a bad cache/bad proxy somewhere between the LMS and client machine, causing either

1. the client machine/device getting a bad copy of the content?
   It that case, may i check/know dose the Rise 360 (and Storyline) has features that we can enable to counter that?
   Something like:
   1. Adding a dynamic random number at the end of the URL/source path? 
      

      www.xyz.com/learning/content/course_123/page1.json?random=12345678

   2. Adding cache control http header to all html pages and for all http requests? 

        <meta http-equiv="Cache-Control" content="no-cache, no-store, must-revalidate, proxy-revalidate" />
        <meta http-equiv="Pragma" content="no-cache" />
        <meta http-equiv="Expires" content="0" />

      objXMLHTTP.setRequestHeader("Cache-Control", "no-cache, no-store, must-revalidate, proxy-revalidate");
      objXMLHTTP.setRequestHeader("Expires", "0");
      objXMLHTTP.setRequestHeader("Pragma", "no-cache");
      objXMLHTTP.setRequestHeader("If-Modified-Since", "Tue, 01 Jan 1980 1:00:00 GMT");

2. the client machine is sending a corrupted copy of the learner's progress to LMS (suspends data?) causes the codes behind to halt? 
   May i check/know does the Rise 360 (and Storyline) has features that we can enable, so that it could check against the data saved onto the LMS is good? so when they resume the course next time, the saved progress downloaded from LMS won't cause as issue? (maybe get a saved copy from the LMS and check if that's the same one it has in the memory/cookie/etc every time saving learner's progress? )
3. the learner might have already lost the connection / timeout? 
   This is hard to find out/or to confirm, as user wouldn't know until they click on any link/button on the LMS and the timeout/re-login message popup in their screen. (even they know, they likely won't admit it anyway, at least for our case, as they want to "finish" eg,skip,  the course as quickly as possible) And from our experience, Rise 360 seems will let user to continue when this happen as far as those content has been loaded into learner's device at the beginning of the course.
   I know, the LMS is supposed to alert learner when this happen. And there is an alert saying there's issue and they need to re-login or something. But this is just a js alert() pop-up that user can easily click "ok" and continue on the e-course... and causing issue later on.

Thank you for reading the post, we are also desperate as well as the admin work that needed to manually handling this is starting to accumulate...