That picture of your Lychee tree loaded with fruits is a sight to see, just gorgeous!!

I noticed you live in zone 10b...part of your issue might be you are not getting enough chilling hours. They require many hours of cooler temps in the winter and also drier conditions to instigate blooms/flowers. I put a website link from lycheesonline.com below that has tips on how to get lychee trees to bloom...most lychee trees do not bloom every year but they suggest some tips that might help get your tree to bloom again...pruning at the right time of year is key plus the "chilling hours" that's required.

With me living in Central FL my chilling hours are not an issue, my 4 year young Lychee tree has bloomed 3x since I've planted it...I follow lycheesonline's advise and prune mine every year in mid July...Good luck!

Lycheesonline.com

Thanks for the information and link.......that's good to know. I have pruned the tree in the wrong month!

You're welcome...I hope it works for you and you get some fruits next year!