I was facing the adb issue yesterday after reboot my laptop.
adb server is out of date. killing...
ADB server didn't ACK
* failed to start daemon *
error: unknown host service
Finally, here is the solution:
Step1: find if the adb port is occupied
> netstat -ano |grep 5037
TCP 127.0.0.1:5037 127.0.0.1:65151 ESTABLISHED 6980
Step2: find the process name
>>tasklist /fi "pid eq 6980
Image Name PID Session Name Session# Mem Usage
========================= ======== ================ =========== ============
tadb.exe 6980 Console 1 5,112 K
Step3: kill that process (tadb.exe for this case)