sound in one channel

Hi, I just installed Volumio on my RPI 4 Hifiberry DAC pro music will play but on right side only. I’ve checked RCA leads to amp and amp plays both sides when I switch amp to play FM radio. The system was playing both sides when I was using Hifiberry OS, what could be gone wrong and how do I fix it?
regards,
Eamonn.

Problem is now sorted, after re-boot all is OK
regards,
Eamonn