In the el-Amarna letters Gubia is the capital of Rib-Addi; his other capital is Sumur, and it is almost permanently under siege, or in danger of being taken.
Gubla is identified by all historians as Byblos; however, a certain wonder is expressed (Albright), why it is called in the letter Gubla, whereas its name in other sources is Gebal (Gwal)
As I could show in Ages in Chaos, in the chapters dealing with the el-Amarna letters, Gubia was the name of the summer residence of Ahab, in the Scriptures given as Izebel (Jezebel), the initial I being a sign of ignominy.
In the Scriptures there is a direct indication that Jezreel was previously called by the name of Queen Jezebel. When her life ended ignominiously, dogs tore her flesh, and the carcass of Jezebel [was] as hung upon the face of the field in the portion of Jezreel, about which they [should] not say, This is Jezebel. (II Kings 9:37). Ages in Chaos I, p. 233.
The location of Gubla (Zebel) in the valley of Jezreel is not established. An indication of its distance from the sea is in the story of the prophet Elijah running all the way before the chariot of king Ahab from the Carmel outlook over the sea to (Je)zebel. From there the son and heir of Ahab tried to escape to Meggido. Archaeological work is needed to locate the place, originally the vineyard of Naboth.