BinsuJiro wrote:
Trevoz,
Nothing has changed since etwo weeks ago when I last updated my firm's web sites. No changes were made to routers, modems or the WiFi Network.
The only change is that before I was running ElCapitan and now I'm running Sierra. It is not a problem at my web hosting service, I can log in on my iPhone with a mobile version of an FTP client.
This is an APPLE OS Sierra problem, just like the many people who are having problems with Safari crashing, because the new system integration does not like the way Apple customers constructed their Bookmarks List. Apple forgets that we are the customers, and they shouldn't bully us the way Microsoft customers are bullied.
I had to actually find the POWWEB website which I did. If their website is any indication (it looks like it hasn't been updated since the late 90s), it's very much doubtful that it's a macOS Sierra problem. Too many people are able to use FTP or connect to Amazon just fine. We use IBM SoftLayer (for nearly a decade - from The Planet and EV1 to SoftLayer to IBM SoftLayer). We also use a lot of other partner providers and have servers in both third party datacenters ("colocation") and our own facilities. I tell you this because of what I am going to say next. I don't want you to misinterpret my statements as something being directed in a way no one would like.
By your own admittance, you don't normally work with the "technical" stuff and thus like someone in such a scenario which I completely understand, you have now fallen into this "bully us" attitude. This means that in a sense - you are not a knowledgeable source able to readily resolve this. Let's take a step back and look at this objectively.
Your website is hosted by a company on what's known as "shared hosting." This is the cheapest of the cheap in terms of hosting offers. Basically, there could be a thousand websites or more on one server (a server, defined in this sense, is a single dedicated system; likely running CentOS or CloudLinux with cPanel).
If Apple introduced changes to macOS Sierra which removed the ability to use certain older cryptographic cipher suites it is possible that negotiation is now failing with the server because the server doesn't use a modern cipher suite.
Another alternative is that based on your hosting environment you may be locked out through an automated trigger for security. If you have an El Capitan Mac lying around, connect it to the same network and same external IP and see if FTP works. If it doesn't, you have your answer.
Your hosting provider is not sophisticated by any stretch of the imagination. Your hosting environment isn't either.
AWS, Azure, GCE, SoftLayer - they all offer cheap "hourly" virtual servers (these are all far more powerful and more sophisticated then what you have). You can quickly setup a CentOS + cPanel server "hourly" at SoftLayer and try to connect. Your total cost to them would be probably about 10 cents. Heck, spend $5 on a GoDaddy hosting package for a month if you are unsure how to configure a server although the cPanel setup wizard is pretty straight forward. The same is true with AWS. Just remember to terminate or cancel the device/instance once you are done.
That's really the only advice anyone can give you right now if, as you said, nothing else in your network has changed. Since you are on a shared hosting platform you can't view the server logs so the only alternative is to test an FTP connection to another server where there is a lot more control.
Honestly, this is probably not the answer you wanted to hear but this is the answer that anyone here should be giving you at this point. Based on your own admittance and your firm's choice in hosting provider, I imagine that you all are completely out of your depth.
Cyberduck and Transmit are my two favorite FTP programs for OS X. They work wonderfully under macOS Sierra. They were just recently updated however so be sure you also have the latest update.