can not send email 5.7.1

Can not send emails getting error 5.7.1 

I can not send emails since yesterday…
…I need them to keep my company “alive”!!!

Could someone, please, HEEEEELLLLLLLLLLLLP???

Hi Marcelo, if you’re having issues with the application’s features such as sending or receiving messages, please be more specific about the application’s behavior.

Also note that as a free license user you’re NOT entitled to use the application for business/commercial use and you have to obtain a valid PRO license in order to use the application, using free license for business/commercial use you’re acting against the Terms of Use and your license will be suspended.

Thank you for understanding,

Hi Charles, what version of eM Client are you currently using on your computer, can you check for the exact version number in Help > About? 
Can you please make a screenshot of the error you’re seeing? What mail service are you using with eM Client?

Thank you,