I have encountered this issue on my MacBook Air (M1 2020, 8 GB RAM, macOS Sonoma 14.4.1).
When I've selected the reference genome hg19 or hg38 and then go to File > Load From Server...
nothing happens. I do not get the dialog box I am supposed to. I have tried restarting the session and even downloading and using IGV Desktop on another MacBook Pro (M1 2020, 8GB RAM, macOS Big Sur 11.7.10) but faced the same issue there.