Why do servers say Event YES and Sentinel NO?

The servers in question have all been configured for both Event and
Sentinel.

I looked in event.cfg

<CONFIG>
<EVENT>1</EVENT>
<CRC32> BB9AE14FF56BBCFDDA1D33334728E9CC</CRC32> ;modified in case serial#
<PROXYACCT>NSMProxy.ADC.HumbleK12</PROXYACCT>
</CONFIG>

Seems like the Sentinel line is missing.

I have gone in several times to nsmadmin and removed and readded and
servers don't come up as sentinals.

Am I missing a step.
Thanks, Lin