Connection suddenly failing with EACCES - Permission denied

I've used Filezilla on the same site with the same password for at least a year. Two days ago Filezilla started showing this message;
Connection attempt failed with "EACCES - Permission denied".
and now doesn't connect.

I haven't changed anything and I don't think the hosting company have (now checking this out). Does anyone know of any reasons this should appear ?

Thanks