An error occurred while saving the commentAnkit Jadia commented
Just try sending a simple "Hi" first and then paste your long message and send it. It will work. :)
A small explanation about why this works. Skype for Business usually sends messages as thread bubbles in groups. So when first message is being sent from your side to other party it cannot be very long. Once you send a small message like "Hi" or something and then if you send the long one it gets clubbed in a group and you won't face any problem.