Blocked again

[MsAmerica]

The other day, having just made 2 or 3 short replies, I assembled a new top-post - I think it was for the BookFo. But it wouldn't post, no matter how many times I clicked.

Then it switched to a screen reading something like:
Error 1015
You are being rate limited.
The owner of this website has banned you temporarily from assessing this website.

So, what's going on? (And, again, why does this pop up only after I've spent the time to put together the post?)

Email MNHQ

Thanks for posting. It looks like our spam controls may have picked you up. This usually happens when someone posts a lot in a short space of time. Normally it gives a ‘cool down’ message, but even when it doesn’t, the block is only temporary and resets quickly. We know it’s frustrating when genuine posters get caught, but these measures are important to stop spammers from flooding the boards. Can we check if you were able to continue posting soon after this occurred?

Just to be clear, this was my FIRST top-post. I think I was short on time, so I just gave up.
Don't you think that maybe after posters have been here six months, they shouldn't be tripped up like that?
Anyway, thanks, just wanted to let you know.