Xperia Z5 camera Error message

[MG_XPERIA_Z5]

Hi. I have an Xperia Z5 which recently had a screen repair at LSG in UK. As expected, it came back as new.
For the first 5 weeks, it worked fine. Now I keep getting an error message "ERROR CAMERA MAY BE IN USE WITH OTHER APP"
I have tried clearing camera cash and even repair software via PC. Still same. Front facing camera works.
Any ideas or should I send it back to LSG.

 

[B. Diddy]

Welcome to Android Central! Does it happen in Safe Mode as well? https://talk.sonymobile.com/t5/FAQ/How-to-boot-your-phone-into-safe-mode/td-p/348008