Buenos días hay algún usuario que hable español, tengo un píxel 8a con android 15c he instalado grapheneos, todo ok, pero al realizar llamadas me deja, sin embargo no me deja recibirlas, cambien de sim por el de otra operadora; el mismo problema, las operadoras son Jazztel y Butik, me puse en contacto por x con el equipo de grapheneos me dieron varias indicaciones que seguí para peor, ni me deja hacer llamadas ni recibirlas. He intentado revertir el proceso con remove non-stock ley, pero ahora ni tan siquiera reconoce el teléfono. A ver si alguien ha tenido un problema similar y sabe cómo solucionarlo, gracias.

Please post in English here even though it's aimed at people who speak Spanish. Would appreciate if you translated your post.

Hopefully someone else uses those carriers and has it working who can respond.

If you're trying to replace GrapheneOS with the stock OS, you need to boot it into fastboot mode and then use the stock OS web installer. It sounds like you removed the GrapheneOS verified boot key and tried to lock again which won't work.

I couldn't call or receive calls until I enabled 2G in the settings. Try that, maybe helps too

Hope I don't step over boundaries here, but translated OPs post with Google translate:

' Good morning there is a user who speaks Spanish, I have a pixel 8a with android 15c I have installed grapheneos, everything ok, but when I make calls it lets me, however it does not let me receive them, change sim for that of another operator; the same problem, the operators are Jazztel and Butik, I contacted by x with the grapheneos team they gave me several indications that I followed for worse, it does not let me make calls or receive them. I've tried to reverse the process with remove non-stock law, but now it doesn't even recognize the phone. Let's see if anyone has had a similar problem and knows how to fix it, thanks.'