This can be caused by a number of issues so I will list out a number of possible solutions
Step 1
The first thing you should do is reboot your device and try Lyric Search again.
This will remove any issue where Lyric search might be frozen.
Step 2
Lyric Search is essentially a web browser that is using the google search engine to search for query matches.
Google sometimes can act strange where a user is not logged into his/her google account. To fix this do the following:
Open google.com in the web browser of your choice on your device.
Log into google.com with your google account.
Close your web browser.
Try Lyric Search.
Step 3
If you use Lyric Search to get a lot of songs in a short time then Google may detect your device as a bot and test you to check that you are actually a human user.
In this case you should see a popup window or some kind of query on the screen?
If so, either answer the query to prove you are a human or wait half an hour for google to release the ip block on your device.
