RTC display stops to change

Hello, I am using EASYPIC5(PIC16F877A) and RTC PCF8583 board from mikroElectronica.
I have connected the RTC on portC and display the time on LCD provided on the board. But sometimes the display stops to change and only resumes upon reset.

Any clues what to do or check. I am using the RTC read and write functions provided in the sample codes on mikroe.com, some times the clock display runs fine for 4-5 hours and sometimes it stops to change after 5 minutes.

Please Help

Thanks