NI 9401 Event Works Only Once

[JScherer]

I have the following code below for my NI9401 module connected to my computer via a cDAQ-9171

This code is built off the following example here: https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000004AvPSAU&l=en-US

For some reason, the event will consistently fire only once. If anyone has an insight, it would be greatly appreciated.