Sending limit exceeded error message

When sending I get an error message:

10:56:34   MailClient.Storage.Application.ItemOperationException: Cannot send message (Email body not accepted due to the following reason: 
10:56:34     "Your message could not be sent. The limit on the number of allowed outgoing messages was exceeded. Try again later. (#5.7.0)

version is 7.1.31849.0

just upgraded to Pro from free


Hello Mike,

eM Client has no limit on number of messages sent so this reflects a server limit. Please contact your email server support to get this server issue solved.

Thank you for understanding.