Question unsupported signal format in every input toshiba tv

Aug 17, 2020
Ok so i just want to make sure if this is a lost cause or i could still fix it or maybe im just missing something

I have a toshiba lcd tv 19s1400vj thats been running fine as a monitor for my pc.
the only input available is hdmi and rca and since i used it for my pc i use hdmi but just yesterday it keep displaying black screen with a " unsupported signal format " written on it. ive been trying connecting my pc to another tv its still fine so its not my pc nor my hdmi cable its just the tv itself.
problem is it keep black screen even if i connect it to other devices (netflix , laptop hdmi ,etc )
my question is, is my tv a lost cause (need to replace the hdmi connector) or is there some kind of workaround for this to fix it?

ps. also tried changing my pc resolution to 800x600 / 720p doesnt work
sry for my english not my main language