sending in pause

Hello
yesterday i set up a send for a newsletter. i had imported of my contacts about 355.. after sending the system blocked the send for problems. then it occurred to me to check the email DB. so i used one of the email check services and it cleared my DB now i have 155 contacts. i uploaded them in mail poet deleting the old ones. i created a new newsletter but the send is paused.
what to do now?
the current db is clean.

thanks

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