This problem happened to me since Minecraft 1.12.2 when I often click on the Multiplayer button I all my server's have their names and IPs disappeared, except for Hypixel i think because it's the first server on list.
Thus, this is how it happened there will a screenshot shown
MrBara
Environment
Operating System: Windows 10 x32 bit
Java Version: Java 8 (The latest version)
Duplicates MC-39583.