If the chlorine mixes with the vinegar you get chlorine gas. It doesn't take much to be a problem.
Anyway, was 1:4 your ratio of spawn to substrate? That is a bit low, but can work in exceptionally-clean environments. 1:1 is much more conservative so will have a higher chance of succeeding, assuming the spawn is clean.
I've never used 100% coir as a sub, but I've found it to be fairly resistant to contamination when I've used it as a top dressing. Expect to lose some jars and trays, and just keep at it no matter what and watch how things go really closely and all of a sudden things 'click' one day and success become the norm and contamination rare. It took me over a year to get mushrooms popping up after I started trying to grow (with many, many hours of work wasted growing everything BUT mushrooms).
One thing that's great to have even if you're not growing fungi is a UV sterilizer light in your HVAC duct. My contamination rates dropped a lot after installing one. Ebay has them for good prices and are not hard to install (just need to drill two 1-inch diameter holes in your duct; I recommend the dual bulb models and try to get around 26 or more total watts, e.g., 2 13-watt bulbs or stronger works well for most dwellings but check for bulb prices since that's your main cost and pick a unit that has cheaper bulbs available).
They go just downstream of the A/C evaporator where the condensation forms so the light zaps any mold spores produced in the condensation pan as well as whatever is floating around in the air. I also had fewer sinus issues at night after installing it (no more waking up with a stuffy nose in an older house I used to live in). Change the bulbs once a year to maintain effectiveness.