Do I quit or keep trying? There is no answer sold by weight.
Sometimes leaving protects you. Other times you abandon the very thing worth the effort.
The Internet has two pieces of advice for almost any problem: "Never give up" and "Pick yourself up and go." Both come with a matching picture. No one knows exactly what situation you are in.
I tend to keep trying. To look for an explanation, to adjust, to see if it is possible. I don't think that any difficulty is a sign that I made the wrong choice. Some things start to work only after a period in which they don't look impressive at all. If I give up at the first discomfort, I can lose something good before I give it a real chance.
But perseverance also has a less honorable version: I continue because it's hard for me to accept that I invested badly. There are no new signs that things can change, only the argument that we have already put too much there. Time, energy, pride. Especially the last one, which rarely appears on the official list.
I find it useful to look at what the next attempt produces. Am I testing something different? Is there availability from the other side as well? Do we have a concrete step or have we just postponed the same discussion? "See you later" can be reasonable for a while. In the end it becomes a method of not deciding.
I don't want to confuse a bad day with a wrong direction. Nor should I use a good day to justify whole months that say otherwise. What matters is the pattern, what actually moves and if the price to continue is one that I choose, I don't just bear it out of inertia.
So I do not place giving up automatically in either the failure or the virtue column. It depends on what I'm giving up. Sometimes I give up something important. Other times I give up only the pretence that it simply has to work out.