Should I be able to use a variable in test data values, for example, the Value Type of Variable and the Value being the Variable name? I have an error!!
I think you have your values reversed columns are typically letters and rows numbers. Try to switch those two and see if that works.
An alternate route would be to assign the variable in the test case.
TD_authentication = TestDataFactory.findTestData(‘pathToTestDataHere’)
String variableName = TD_authentication.getValue(1, 1)