Hey try:
/minecraft:give @p minecraft:oak_sign{BlockEntityTag:{Text1:'{"text":"[RoyalMinez]","clickEvent":{"action":"run_command","value":"mrl reset s2stone-mine -s"},"bold":true,"color":"red"}',Text2:'{"text":"Right-Click","bold":true,"color":"aqua"}',Text3:'{"text":"Reset The Mine","bold":true,"color":"aqua"}',Text4:'{"text":"[RoyalMinez]","bold":true,"color":"red"}'},display:{Name:'{"text":"MRL sign"}'}}