ADB server not starting in Unity

Question

I have installed Unity 2019.4 with the Android SDK/NDK. An ADB server cannot start with this error:

UnityEditor.Android.Command.RunWithShellExecute (System.String command, System.String args, System.String workingdir, System.String errorMsg) (at <303ae0e7a8d8441ab049e592bd1e2100>:0)
UnityEditor.Android.ADB.StartServer () (at <303ae0e7a8d8441ab049e592bd1e2100>:0)
UnityEditor.Android.ADB.Run (System.String[] command, UnityEditor.Android.Command+WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg) (at <303ae0e7a8d8441ab049e592bd1e2100>:0)
UnityEditor.Android.AndroidDeploymentTargetsExtension.GetKnownTargets (UnityEditor.DeploymentTargets.IDeploymentTargetsMainThreadContext context, UnityEditor.ProgressHandler progressHandler) (at <303ae0e7a8d8441ab049e592bd1e2100>:0)
UnityEditor.DeploymentTargets.DeploymentTargetManager.GetKnownTargets () (at <7d90b28560b644ce87b8263efcc36eed>:0)
UnityEditor.Android.AndroidBuildWindowExtension+<>c__DisplayClass31_0.<SpawnFetchTargetsThread>b__0 () (at <303ae0e7a8d8441ab049e592bd1e2100>:0)
System.Threading.ThreadHelper:ThreadStart()

I tried running adb in the terminal but it could not start either. I have already made bypasses through in the windows firewall. It had this output:

* daemon not running; starting now at tcp:5037
could not read ok from ADB Server
* failed to start daemon
adb.exe: failed to check server version: cannot connect to daemon

I am using windows for this.

Answer 1

Another solution that worked for me was.. closing other softwares that use other versions of ADB. In my case, it was Android studio that was running another version of ADB.