ERROR: No bootable media after removing & reinserting SSD

I had a working Qubes setup for some time. Recently I removed my internal Qubes SSD (to prevent any damage to it) and attached an external USB SSD to install different OS in that. After I reattached my Qubes SSD back to system it’s showing no bootable media found in UEFI. This SSD is appearing in file system of other OS. I believe something might be wrong with GRUB however can’t figure out what.