Same thing here - I had stopped using Airdroid about 7-8 months ago on my "old" phone (was a Samsung Galaxy S3) because of the issue and had been reading some of the posts since then and though I would give it another try - now have a LG Optimus Exceed and still same thing: I can receive SMS on my computer fine, can call up my contacts, etc (pretty much everything EXCEPT send SMS). It let's me compose them and when go to send them, little envelop just starts flashing across. Sometimes it stops and I get message that the send failed - but most times the envelope just keeps on going.