The suggestion to do an update is a fair one if the index is marked as failed which indexvolumereply would report.
FYI Sergy, the option you mention is update(which isn't wrong) but what it does is just request that EV once again tries to add items ot the index, it's not like it rebuilds the entire index, it just adds items that need to be added to the index. So it can be very quick indeed.
What EV does, is if it gets problems add items ot an index a consequtive number of times, it marks the index as failed (to stop further errors being reported). So you can then use the update command to get EV to try again. You should then investigate the ev event log and avtrace.log file(within the index) to see why the index has marked as failed and resolve that root cause.