WIFI connection problem topic

My wife has a problem with connecting to our wifi on her S5. It either does not connect to the network or if it does it cnnot access Internet. The signal is strong and we have a lot of other divices (Nexus ones, laptops etc) which connect and work without any issue.
Some of the router settings are as follows:
Mode: 802.11b/g/n
Security: WPA2-PSK
WPA encription: AES