I have the same relay on a breadboard and in a perf board and it seems to be soldered together the same way. When it is in the breadboard, the relay and diode on its coil works.
If it works in one situation and not the other then it is not wired in the same way even though it "seems" to be. Otherwise physics falls apart and that will never do.
As you have the board only you can find out what is wrong but it is wired up wrong in the circuit that doesn't work.
any other trouble shooting approaches?
1) Use test equipment and be comfortable with what it is telling you.
2) Trace a signal from origin to the final component, where you fail to find it your mistake is between there and the last good point.
3) Never make a measurement without having an expectation of what the answer should be.
4) Get an oscilloscope and learn how to use it, electricity is invisible an oscilloscope is your eyes.
5) When something simply can not be happening it isn't. You are misinterpreting something.
6) Most important to learn - all the mistakes are yours - even after 45 years I can make a mistake wiring up.