5 concurrent connections at the same time allowed

I have a problem while using the Free Api. I’m getting the message: For this API KEY only 5 concurrent connections at the same time allowed.
I’m processing a image every 3 minutes. So the 500 call/day limit isn’t a problem.
Anybody have a idea of how I can fix this issue?
Thanks.

Please try again now. We made some changes to the free OCR API and it should be better now.

Thank you. Now it is working fine.