chronic 503 error

chronic 503 error on my mac (i posted this a few days ago but i wrote the wrong error 😭) i am finally trying to fix this problem, so if there’s anyone who has any solutions for this PLEASE LMK (in the simplest terms, i know nothing about computers) for months now (probably since we got new router) i have not been able to access any website at all through Safari on my Macbook. nothing works at all even tho i am connected to wifi and my phone works just fine on the same wifi. i will type anything into safari and its error 503 everytime, i have no idea how to fix this. i haven’t used my laptop for months because of this.