Some themes and plugins have <a href="%1$s" target="_blank">known conflicts</a> with Jetpack – check the <a href="%2$s" target="_blank">list</a>. (You can also browse the <a href="%3$s" target="_blank">Jetpack support pages</a> or <a href="%4$s" target="_blank">Jetpack support forum</a> to see if others have experienced and solved the problem.)