traccar client app not install

Good day everybody,

I'm facing one problem after generating the apk in android studio. There is no problem or error while upload and build the application i had made some changes and generate sign release apk . when i try to install in android phone its show me message that "App not installed" ! i have try many times in different phones but still same problem! any suggestion of this problem. link of the photo photo

Thanks

Same happened to me :(
It seems to be a problem that the uninstall of the official build don't remove the certificate.
My temporary workaround was to select debugRelease in order to work.