Problem with the ML ALS algorithm

[Steve Pruitt]

I get an inexplicable exception when trying to build an ALSModel with the 
implicit set to true.  I can’t find any help online.

Thanks in advance.

My code is:

ALS als = new ALS()
                .setMaxIter(5)
                .setRegParam(0.01)
                .setUserCol("customer")
                .setItemCol("item")
                .setImplicitPrefs(true)
                .setRatingCol("rating");
ALSModel model = als.fit(training);

The exception is:
org.apache.spark.ml.optim.SingularMatrixException: LAPACK.dppsv returned 6 
because A is not positive definite. Is A derived from a singular matrix (e.g. 
collinear column values)?
                at 
org.apache.spark.mllib.linalg.CholeskyDecomposition$.checkReturnValue(CholeskyDecomposition.scala:65)
 ~[spark-mllib_2.11-2.3.1.jar:2.3.1]
                at 
org.apache.spark.mllib.linalg.CholeskyDecomposition$.solve(CholeskyDecomposition.scala:41)
 ~[spark-mllib_2.11-2.3.1.jar:2.3.1]
                at 
org.apache.spark.ml.recommendation.ALS$CholeskySolver.solve(ALS.scala:747) 
~[spark-mllib_2.11-2.3.1.jar:2.3.1]