I created a few different flows to capture form responses and then send reply messages that the form was received. The flows also had the ability to send attachments. It has worked perfectly then the last request came in and we could not open the pdf attachment. I got the message 
After investigating I also tried to send a test with a Word file and was also unable to open the file. 
Below is my flow:



I don't understand how everything works for a while and then stops working. Please help me with a solution. Thanks
Diana