Getting _grokparsefailure on adding a tag

Here is a filer statement

filter {
grok {
add_tag => ["name"]
output {
elasticsearch {
hosts => 'host'
flush_size => 500

Can anyone help?

Please edit your post and move it to the Logstash category where it belongs.

Why are you using a grok filter just to add a tag? Use a mutate filter instead, or add a match option to actually use the grok filter as a grok filter.