Led problems

[kole]

Hoping someone can help me out. I have a diy led setup from MOdularled. This is my second build. This build has an inventronics 96watt driver driving 21 royal blue led boards. it is dimmed by my Apex with the VDM miodule. Problem is the blues are having an issue. Last week I noticed 1 of the LEDs on the first board in the string wasn't lighting up but all the rest were oK. Last night I noticed none of the blues were lighting up. I removed the first Led from the circuit and connected the driver to the second led board and the blue light worked. This morning the blue lights came on but when I got home from work the blues are off. My white string of Leds work perfectly as does the first DIY led setup on my other tank. Whats happening any ideas?