How to connect RTC

I have set up

dtoverlay=i2c-rtc,pcf8563

[ 6.208687] rtc-pcf8563 10-0051: pcf8563_write_block_data: err=-121 addr=0e, data=03
[ 6.208722] rtc-pcf8563 10-0051: pcf8563_probe: write error
[ 6.208737] rtc-pcf8563: probe of 10-0051 failed with error -5