The problems of Wi-Fi and Bluetooth usually appear when you find a new smartphone and there have also been reports of problems with the Galaxy S9 and Galaxy S9 Plus with connectivity.
Wi-Fi problems
We turn off the device and the ruoter for at least ten seconds, turn on again and try the connection.
Go to Settings> Energy Saving and make sure that this option is disabled.
We use the Wi-Fi Analyzer to verify how busy our channel is and switch to a better option.
We forget the Wi-Fi connection by going to Settings> Wi-Fi and touching the connection we want, then select "Forget". We re-enter the details and try.
We make sure that the router's firmware is updated.
We confirm that the applications and software on the device are up to date.
Go to Wi-Fi> Settings> Advanced and take note of the MAC address of the device, then make sure that access is allowed in the MAC filter of the router.
Some users have found that disabling the Hotspot 2.0 feature seems to solve many problems with Wi-Fi.
Bluetooth problems
We verify the manufacturer's manual of the device and the car and re-establish your connections.
We make sure not to lose one of the two parties in the connection process.
Go to Settings> Bluetooth and make sure you do not need to change anything.
Go to Settings> Bluetooth and remove all previous pairings and try to reconfigure them from scratch.