Error F-5 on Washing

Hi,
I have a washin mashine and It gives error F-5.
mashin take in water and turne in some minute then it sees that it is unable to send out dirty wate.
I have chekd that tubes are clean.
Mashin is an Ariston AVD129 and I don't find any information on the internett about this error . I thought maybe it is similar to other waskin mashine.
How can I fix this problem?
I appreciate if you answer my question.
Thanks
Regards
Landari