I got the 50 questions limit message.
How long does this probation lasts?
I believe that the limit is based on a rolling 30 day period. So, if you've asked 1 question 30 days ago and another 49 over the other 29 of the 30 days, as of tomorrow you'll be able to ask another question.
Bear in mind that the stackexchange day runs from midnight UTC (aka GMT) so the new day will start when midnight ticks over in London, UK.
You will probably have to wait until the first of those questions drop out of the 30 day window. It's not a ban, just a limitation.