Timezone lookup for: <TZ> ... ERROR: Timeout

[ronzelver]

Since a couple of days the timezone lookup always runs into timeout.
I've already tested the response from 'timezoned.rop.nl' manually which responds normal:

$nc -u timezoned.rop.nl 2342
amsterdamOK Europe/Amsterdam CET-1CEST,M3.5.0,M10.5.0/3

I've also tried to increase the default timeout from 1500 to 5000 ms, but no result.