How to deal with the UTC format by date plug-in

[ipv6ok (czm)]

my nginx log timestamp like this:
20190425T092956Z

but use date plug-in can't deal !
logstash code:

date { match => ["timestamp", "ISO8601","yyyyMMddHHmmssZ"] }

IN kibana show @timestamp no change
logstash version 6.6.1

[Badger]

date { match => ["timestamp", "yyyyMMdd'T'HHmmss'Z'"] }