There is a definate nutrient deficiency. Nitrate should be 10 to 20ppm for plant health. To be at zero (i would say your test looks more like 5ppm) you either have very low bioload or the other plants are consuming all the nutrients, or some of both. If your fish arent producing enough nitrate for your plants health you should look at dosing a fertiliser that contains an appreciable amount of nitrogen. Most dont contain any.
Luckily for you easy green is one of the few that does contain nitrogen. But you arent dosing enough if your nitrate is still showing as zero. From recollection the recommended dosage of easy green should increase nitrate by 6ppm. I would increase the dosing to the recommended twice weekly, and see where the nitrate gets up to. If you still are showing very low nitrate then you may need to up the dosage even more. Remember that anubias are very slow growing, so it could take several months to see any improvement in the plant.
You might want to look at the estimative index method for dosing nutrients. This basically involves dosing high levels of nutrients throughout the week and then a big weekly water change to bring the nutrients back down before starting your weekly dosing schedule again.