[Blueprint] (https://i.sstatic.net/GPoxaNRQ.png)

here im attaching the blueprint logic .

iam getting this error
Blueprint Runtime Error: “Accessed None trying to read property Dynamicmaterialinstance”. Node: Set Scalar Parameter Value Graph: EventGraph Function: Execute Ubergraph BP Slideshow Blueprint: BP_slideshow

enter image description here

i tried multiple times but ended up on same page.