Since I bought my phone, the "googlr Play Store"responds up until I have to download or update an application (this happens with all applications) an "Skype-free IM & video calls" could not be downloaded due to an error. (Error retrieving information from server. [RPC:S-7:AEC-723NB-FNZI-O7FXE])error message keeps popping up. how can I fix that?

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