How to troubleshoot electronic issues?
The title of your question could be more specific. "How to troubleshot electronic issues" applies to almost every question asked here ;-)

Let's see if we can help you...

1 - The relay module has 5V in its codename, so the module's VCC has always be feed with 5V, or the relay's coin would not turn on, and there's no news that it didn't worked at 3v3. So, never connect the module to another voltage. If possible, measure the voltage with a multimeter to find if the source is really 5v that you expect it to be.

2 - But Wemos Lolin (I've just discovered what is it) works at 3V3. So, the output from WL's D5 pin, when "HIGH" is just 3V3, and I think that this is the reason why your circuit is not working properly 

Even if it by chance it dit worked for some hours (just a temporary luck), you should never build a circuit relying on a 3v3 digital output to drive a 5V input (there's exceptions, but this is the kind of thing that your really should know what you're doing and would not be asking about this in stackexchange). 

3 - The final answer is simple:

Wemos Lolin output and the relay module can not be directly connected, with or without a resistor, whatever the resistor value. 

They only can be connected via a level-shift circuit, what can be a converter module like this shift-level, or a transistor. Google about:

wemos lolin to 5v relay module transistor level shift

trigger  5v relay module with 3.3v digital output

Good luck!