Hi,

Is there a blue light showing on the bottom right hand corner at the front of the speaker when you switch it on?

If not it means that the battery is flat and needs to be charged. Plug in the charging adapter and see if the light comes on.

If it does let it charge for a while then try to connect to your phone.

If it does not there may be a problem with either the charger, the charging circuit in the speaker or the battery in the speaker.

If it does come on when you switch on is it flashing rapidly or slowly?

Rapidly indicates that it is waiting to be paired. Slowly indicates that it is already paired.

Here is the Ifixit guide to troubleshoot your speaker

Photive Hydra Troubleshooting