Photos not loading

Hi,
My photos are not loading and getting this message:

Failed to load resource: the server responded with a
status of 504 (Gateway Timeout)

an example can be seen here:

https://rparisi.com/galleries/maternity-joy-2/

How do I resolve this?
It is something I need to do in my settings?
Thank you,
Renee

https://www.ads-software.com/extend/plugins/jetpack/