For every activity it will have one property like waitfor ready property the default time is 30 sec so here in your case what is happening is it is waiting for the element to appear and it will wait for that time if it is not appear it will throw this kind of errors
Anil_G
ashokkarale
jinal.shah
Gautham_Pattabiraman
postwick
chandreshsinh.jadeja
vrdabberu
Ajay_Mishra
sven.wullum1
Vyshnavi_Nalumachu