DAX count and filter problem

I’m trying to create a column (Sum of Practice Quiz Submission) in a table (U_DIM_LM_USER ) which will look up a common value (USER_ID) in another table (U_FCT_LM_QUIZ_SUMISSION) and return a count of a specific value (practice_quiz) from another column in that table.  The result will lopk like the above.

I’ve used this DAX formula, which Power BI doesn’t flag up any errors with, but I don’t get any numbers in my Sum of Practice Quiz Submissions column.

Practice Quiz Submissions = CALCULATE(COUNTROWS ( U_FCT_LM_QUIZ_SUBMISSION ), U_FCT_LM_QUIZ_SUBMISSION[QuizType] = " practice_quiz ",FILTER(ALL(U_FCT_LM_QUIZ_SUBMISSION),U_FCT_LM_QUIZ_SUBMISSION[USER_ID]=U_DIM_LM_USER[User_ID]))

Can anyone see where I’ve gone wrong? Thanks in advance.