/wd/hub/session//appium/app/background

am running my test on single device , there are multiple testcase, and am making sure that i quite the driver every time, but it seems like when i run one testcase it work fine, but when i run testcase one by one then i get error

-> error: Unexpected error. The URL ‘/wd/hub/session//appium/app/background’ did not map to a valid resource

logs are shown below:-

{“platform”:“LINUX”,“webStorageEnabled”:false,“takesScreenshot”:true,“javascriptEnabled”:true,“databaseEnabled”:false,“networkConnectionEnabled”:true,“locationContextEnabled”:false,“warnings”:{},“desired”:{“platformName”:“Android”,“platformVersion”:“7.0”,“deviceName”:“ce12160c41788c0705”,“app”:"/Users/jebran/Downloads/uk.co.vanquis.app.apk",“appPackage”:“uk.co.vanquis.app”,“appActivity”:“md5c94cdddfdaba12205d403d011df87b56.MainActivity”},“platformName”:“Android”,“platformVersion”:“7.0”,“deviceName”:“ce12160c41788c0705”,“app”:"/Users/jebran/Downloads/uk.co.vanquis.app.apk",“appPackage”:“uk.co.vanquis.app”,“appActivity”:“md5c94cdddfdaba12205d403d011df87b56.MainActivity”,“deviceUDID”:“ce12160c41788c0705”,“deviceScreenSize”:“1440x2560”,“deviceModel”:“SM-G930F”,“deviceManufacturer”:“samsung”}
[HTTP] <-- POST /wd/hub/session 200 9369 ms - 870
[HTTP]
[HTTP] --> POST /wd/hub/session/e317b299-c779-49c5-a7cb-1f1eeb44aa3f/timeouts
[HTTP] {“type”:“implicit”,“ms”:30000}
[MJSONWP (e317b299)] Calling AppiumDriver.timeouts() with args: [“implicit”,30000,null,null,null,“e317b299-c779-49c5-a7cb-1f1eeb44aa3f”]
[BaseDriver] MJSONWP timeout arguments: {“type”:“implicit”,“ms”:30000}}
[BaseDriver] Set implicit wait to 30000ms
[MJSONWP (e317b299)] Responding to client with driver.timeouts() result: null
[HTTP] <-- POST /wd/hub/session/e317b299-c779-49c5-a7cb-1f1eeb44aa3f/timeouts 200 4 ms - 76
[HTTP]
[HTTP] --> POST /wd/hub/session//appium/app/background
[HTTP] {“seconds”:1}
[HTTP] No route found. Setting content type to ‘text/plain’
[HTTP] <-- POST /wd/hub/session//appium/app/background 404 1 ms - 80
[HTTP]
[HTTP] --> DELETE /wd/hub/session/e317b299-c779-49c5-a7cb-1f1eeb44aa3f
[HTTP] {}
[MJSONWP (e317b299)] Calling AppiumDriver.deleteSession() with args: [“e317b299-c779-49c5-a7cb-1f1eeb44aa3f”]
[BaseDriver] Event ‘quitSessionRequested’ logged at 1548949955650 (15:52:35 GMT+0000 (GMT))