Troubles using I2C/IIC bus

[ksarz]

I am having troubles using I2C interface on KC868-A6-V1. Programming using Arduino IDE 2.3.6
So I tried running programmes for digital inputs, relays and the built-in "Wire Scan" example with a sensor connected and none of them work. Here are the error texts:

Wire Scan:
"EScanning for I2C devices ...
E (522034) i2c.master: probe device timeout. Please check if xfer_timeout_ms and pull-ups are correctly set up
Error 5 at address 0x01
E (522094) i2c.master: probe device timeout. Please check if xfer_timeout_ms and pull-ups are correctly set up
Error 5 at address 0x02
(all the other adresses)
(529474) i2c.master: probe device timeout. Please check if xfer_timeout_ms and pull-ups are correctly set up
Error 5 at address 0x7D
E (529534) i2c.master: probe device timeout. Please check if xfer_timeout_ms and pull-ups are correctly set up
Error 5 at address 0x7E
No I2C devices found"

Relays:
"E(76561) i2c.master: I2C hardware NACK detected
E (76561) i2c.master: I2C transaction unexpected nack detected
E (76561) i2c.master: s_i2c_synchronous_transaction(924): I2C transaction failed
E (76567) i2c.master: i2c_master_multi_buffer_transmit(1186): I2C transaction failed"

Digital inputs:
"E (9060) i2c.master: I2C hardware NACK detected
E (9060) i2c.master: I2C transaction unexpected nack detected
E (9060) i2c.master: s_i2c_synchronous_transaction(924): I2C transaction failed
E (9066) i2c.master: i2c_master_receive(1240): I2C transaction failed
KEY1 PRESSED
KEY2 PRESSED
KEY3 PRESSED
KEY4 PRESSED
KEY5 PRESSED
KEY6 PRESSED
KEY7 PRESSED
KEY8 PRESSED"