Insomnio translates directly to "insomnia." It's a word that immediately conveys a sense of sleeplessness and longing, which is central to the song's theme.
In the lyrics, the artist sings, "Que con tu partida me provocaste insomnio" (That with your departure you caused me insomnia). This word perfectly encapsulates the emotional turmoil and restless nights experienced after a breakup, making it a powerful and relatable choice for a push notification.
The narrator spends the whole song losing an argument with his own phone. He is drinking alone again, and the reason he gives himself for not calling is pride: "¿dónde fue que perdí / El orgullo para sentir que quiero hablarte" ("where was it that I lost / the pride to feel that I want to talk to you"). He loses it anyway. He goes out to forget her, gets drunk, dances with someone else, and then reports all of it straight back to her: "te mando un audio solo pa' contarte" ("I send you a voice note just to tell you").
The title is the punchline. Sleeping would mean dreaming about her, so he stops sleeping: "Y ya no duermo para no soñarte / que con tu partida me provocaste insomnio" ("And I don't sleep anymore so I won't dream of you / because with your leaving you gave me insomnia"). She is barely present in her own breakup song. "Apagando tu luz y celular" ("Turning off your light and your phone") is the only thing she does across all thirty-eight lines, and it is what leaves him awake.