thank you very much for your advice :
i was able to solve it:
the problem was with the link and the variables:
img src=“https://servername/graph.php?&id={{ $value[‘port_id’] }}&type=port_bits&lazy_w=805&device={{ $value=[‘hostname’] }}&?=yes&height=486&width=1656&from=end-1h”
this is what i needed on my e-mal.
