Put Community MVP12M into Google and the second listed result goes to:
MVP12M spec PDF
4th item down on the left of the screen.
I didn't know that Fender made DI boxes; your link gives a 404.
Without knowing the exact make and model (your link didn't give that info), here's a few things to try.
1. turn the monitors off. Let's concentrate with just getting the guitar into the desk first and we can worry about where it's sent later.
2. plug the output from the acoustic guitar into the jack input on the DI box, using a guitar cable that you know works.
3. Using a known working mic lead, plug one end into the DI box output and the other into the snake.
4. disengage any pad switches on the DI box.
5. go to the other end of the snake and plug the corresponding output connector into the mixing desk.
6. have someone play the guitar.
7. PFL the guitar channel and gradually bring up the gain until it registers nicely on the desk (gain structure is another ball game).
That should get you working.
If that doesn't work, you will need to work through the signal path replacing cables. Do you have a cable tester? Best $35 I ever spent. Saves a lot of time.
Have you tried a different guiar? Do you know that it works?
You will need to be methodical. Replace the guitar lead, replace the mic lead, try a diffent DI box, try a different snake channel, try running a long mic lead to bypass the snake (for diagnostic purposes; not recommended as a long term solution), try a different desk channel, and so on.
Something in the signal chain isn't right. Once you find that, you can work on the solution.