In my experience, it's usually a network communication between the Flash client and the game's server. Try reloading. If that doesn't help, clear the cache and reload again. Also, it might be useful to try from another browser.

If none of this helps, please follow the steps here. Also, write here, on this topic, ASAP and specify what units and how many of them do you want to buy and, if possible, I'll try to get a Support agent to do that for you before your offer expires.

I tried a different browser, clear the cache and everything. Still doesn't work. I can buy whichever other unit I want, but won't let me get any HMS Invincible's. It's just one that I would like to buy (that's my last unit out of 20 that I could get with this discount). And the discount is going to expire in 2h and 40 minutes approx.

lizzy.clary said:

Thanks for trying to help. It's going to run out right now so I will just buy something else instead of HMS Invincible. Let me know if you figure out why this had happened/is happening. :)

I just asked the Support if they can get you one. If you don't use this up, please let me know. Otherwise, I'll revoke my request.

lizzy.clary said:

I would love to get one, but only if it's for that discounted price. If not, then it's okay. Thank you!

I have checked your logs and found that you used the discount completely and purchased 10 Units. Unfortunately, I am unable to purchase the HMS Invincible for you. Nevertheless, I have reported the issue to the devs. It will be resolved with the future game updates.

Agent Pavel said:

you used the discount completely and purchased 10 Units.