Server Issues

Upon the first few minutes after creating a server with the unmodified official server software from Minecraft.net players get randomly kicked. There are no differences wether the .exe or he .jar file is used to host the server. Player get kicked and in the logs the following appears:

(username) lost connection: TranslatableComponent{key='disconnect.genericReason', args=[Internal Exception: java.io.IOException: Eine vorhandene Verbindung wurde vom Remotehost geschlossen], siblings=[], style=Style{hasParent=false, color=null, bold=null, italic=null, underlined=null, obfuscated=null, clickEvent=null, hoverEvent=null}}