AuthDigestNonceLifetime 300
The AuthDigestNonceLifetime directive controls how long the
server nonce is valid. When the client contacts the server using an
expired nonce the server will send back a 401 with
stale=true
. If <time> is greater than 0 then
it specifies the number of seconds the nonce is valid; this should
probably never be set to less than 10 seconds. If
<time> is less than 0 then the nonce never expires.