You said 2:3:1, what would that measurement be per 5 gallon ?
No, that's 2 parts micro to 3 parts gro to 1 part bloom. A part can be anything. A teaspoon, a milliliter, an oz.
If you look at the charts you posted, it calls for 10ml micro, 15ml gro, 5ml bloom for aggressive growth. That would be a ratio of 2:3:1. In other words, whatever amount your bloom part is, you want 2x that amount for the micro, and 3x that amount for your gro part.
Since you're using 15ml per 5 gallon of each micro, gro, bloom, you are using a 1:1:1 ratio (15:15:15), which is for mild veg growth.
They are calling for 10:15:5 per gallon, so that would be a 2:3:1 ratio with 1 part being 5ml (the bloom part). That is too high of an EC, but you want to use that ratio (2:3:1) in order to have the NER (nutrient element ratio) be balanced and then dilute the mix so the EC is appropriate for the crop you're growing since these nutrient EC's are not specific to cannabis.
You want to use that NER (2:3:1 micro, gro, bloom) and dilute it down to the EC around 1.2-1.6. You also want 4-5ml per gallon of the calmag if you're using RO water.
The ideal pH for coco is 5.8. Your pH is a bit high but 6.1 wouldn't cause an issue like this unless that 6.1 isn't really 6.1.
When was the last time you calibrated your pH pen? It should be calibrated once a week, no matter how expensive the pH pen is.
Autopots aren't the best for coco because coco wants to stay moist at all times and when you wick from the bottom up, you are not getting runoff which helps push the salts out of the medium, so you may need to top feed by hand to push the salts out.
You should flush by hand with an EC of about 1.2 of a ratio of 2:3:1 micro, gro, bloom top fed until what comes out of the bottom of the pot is 1.2 and then put it back in the Autopot system and resume because I think you have a lockout or your pH pen is way out of calibration. Dip it in some 7.0 reference solution and see what it reads.