My nexus 6p never automatic to sleep

[AC Question]

My nexus 6p never automatic to sleep i went to settings and screen then sleep mode it already 15 second. Then i leave my phone a wake to check it the sleep mode is working or not then i find out it not working. can you help me guys and sorry for my.bed English. Thanks

 

[Tahir AL]

My nexus 6p never automatic to sleep i went to settings and screen then sleep mode it already 15 second. Then i leave my phone a wake to check it the sleep mode is working or not then i find out it not working. can you help me guys and sorry for my.bed English. Thanks