Error Error while Launching activity during real machine debugging of Android Studio

Android Studio run app error Error while Launching activity

error content:
Error while executing: am start-n "com.example.xhdqzz.myapplication/com.example.xhdqzz.myapplication.MainActivity"-an android.intent.action.MAIN-c android.intent.category.LAUNCHER
Starting: Intent {act=android.intent.action.MAIN cat= [android.intent.category.LAUNCHER] cmp=com.example.xhdqzz.myapplication/.MainActivity}
Error type 3
Error: Activity class {com.example.xhdqzz.myapplication/com. Example.xhdqzz.myapplication.MainActivity} does not exist.
Error while Launching activity
I have just contacted adb and tried many ways to solve it

Jun.17,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1b9cdd9-376e5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1b9cdd9-376e5.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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