HP Smart Tank 750 Error E3

[Dimosthenis]

There is no paper jam anywhere.
Every sensor works great.
I have tried brand new printheads.
The E3 error remains.
Any thoughts anyone?
Thanks in advance.

[Lance15]

Maybe too much friction? Maybe the carriage rod needs lubrication.

[Lance15]

If you look at the carriage rod, do you see grease, or, is it clear?