Trouble Feeding Eyelash Viper

Hello, new member here.

I bought a young eyelash viper in mid-May of this year. For reference, the eyelash viper was born in November of 2022 making him approximately six months old when I got him and eight months as of now.

According to the notes of the guy I bought the snake from, the snake was consistently eating pinkies with dates denoting the times that the snake supposedly ate them. Two weeks after I got the snake, I was able to successfully (and easily) feed him a pinky. Ever since, I have had absolutely no luck.

For clarification - while this is my first snake, my father has been very present in the process being as he previously bred green tree pythons and also owned both gaboon vipers and rhino vipers and had no problems keeping them. Even he doesn’t quite understand where the issue is with this snake.

Hopefully one of you can help me (well really the snake) out here.

Thank you,
Mark