Can't download Apps

[Hammeke]

Hello,

my boyfriend has a problem with his sony xperia SP,

when we try to download an app, he blocks and gives a fault

'Error while retrieving information from the server
[RPC:S-7:AEC-7]'

Does anybody have an idea how we can solve this?

[Thommo]

Open Settings then Apps and swipe to All - Then locate and open Play store or any other app associated with the Play store and tap on Force stop then Clear cache and Clear data then reboot and test

[Uliwooly]

If that doesn't work then 

settings > accounts > google > remove your google account > re-add it