Gzuuus … you were right all along. My timestamp was not formatted properly. 

BUUUT in my defense, NDK event.publish() doesn’t report errors from relays … and relays also don’t report useful errors when fail to write. 

Had to deconstruct NDK to even get a stupid error logged like this (as returned from my relays) :
“wrong index for variant”

Nostr sucks for debugging.