issue after (around) 5 days runtime in background

[ChristianVirtual]

After around a week running my python 3.4 script (started nohup & in background) get messages in the log file

2016-10-07:07:55:10:write socket descriptor is not ready after 10
2016-10-07:07:55:20:write socket descriptor is not ready after 10
2016-10-07:07:55:30:write socket descriptor is not ready after 10

and no more notifications are send to iOS. Once I restart the script the notifications again get send.

Wonder if this can be a memory leak or user error on my side; everyone seen it before and have a solution ? Or a bug ?

Server OS is CentOS; python 3.4 and still send against the sandbox of APNS