implementation ‘’ [on hold]

i am trying to connect my app with firebase.i follow all the procedure accordingly still i am having this problem from last 2 hours.

my app performance stuck here.its just loading from last 2 hours

dependencies {     implementation fileTree(dir: 'libs', include: ['*.jar'])     implementation ''     implementation ''     testImplementation 'junit:junit:4.12'     androidTestImplementation ''     androidTestImplementation ''     implementation '' } apply plugin: '' 

I watch different video and dependencies changed but still problem is not solved.

this line of code continuously showing Red underline