can't connect to ftp server since 10.12.4

I get NSURLErrorDomain 1002 when I try to connect to a remote server. These are site I have regularly connected to with no problems until my Mac updated to MacOS 10.12.4 on Apr 7, 2017, I've tried three different ftp clients (FlashFTP, Viper FTP and ForkLift), same results. I can get on to the sites on my office windows pc.

MacBook Pro (Retina, 15-inch, Late 2013)

Model Name: MacBook Pro

Model Identifier: MacBookPro11,2

Processor Name: Intel Core i7

Processor Speed: 2 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 6 MB

Memory: 8 GB

Boot ROM Version: MBP112.0138.B25

SMC Version (system): 2.18f15