Text to Speech Stops Working in the middle of passage

[AprilClopton]

We are using Mastery Connect for benchmark testing and are having the problem of text to speech beginning to read the passage but then stopping.  The students have to repeatedly click stop and play over and over until the entire passage is read.  Has anyone else experienced this?  This is happening on multiple campuses and multiple tests.  I have not been able to find a link between the students with the problem.  It is random and usually affects 3-4 per class.