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"Socket is not connected" on iPhone: fixing SMB connection errors

By Isaac Griffiths, developer of SMBDrop ·

You type the server's address into the Files app's Connect to Server, tap Connect, wait for what feels like a long time, and get:

There was a problem connecting to the server. Socket is not connected.

As far as I can tell from how the error behaves, it means the iPhone never managed to open a network connection to the SMB service on that address (TCP port 445), or the connection dropped straight away. Apple doesn't document it, so take that as my reading rather than gospel. What the reports do show is that it's rarely fixed by changing the password. It's fixed by getting the address, the network or the firewall right.

Here are the causes I found in Apple Community threads and forums, most common first.

1. You typed the computer's name instead of its IP address

The most upvoted self-answer in the Apple Community thread "Connecting to server in the Files app on iPhone" is simply: find the server's IPv4 address and use smb:// plus that address. A how-to with iOS 26 screenshots gives the same advice for this exact error. An iPhone resolves names through your router's DNS and through Bonjour (.local names), so a bare Windows PC name doesn't always resolve. The IP address is the reliable test.

Find the IP address:

Then enter smb://192.168.1.20 (with your own address) in Connect to Server.

2. You used the IP of the wrong network adapter

Windows PCs often have several adapters: Wi-Fi, Ethernet, a VPN, and virtual ones such as Hyper-V's vEthernet. Each has its own address in ipconfig, and only one is on your home network. One user in this thread had copied the address from the wrong adapter; using the right one fixed it straight away. Your home network address usually looks like your iPhone's own (compare with Settings → Wi-Fi → (i) next to your network).

3. Port 445 is blocked or nothing is listening

If the address is right but the SMB service isn't reachable, you get the same error. As one reply on r/ios put it, "That's a port issue." Check:

4. Nothing is actually shared, or the account has no share permission (Windows)

A Windows PC with no shared folders has nothing to offer. One person realised they hadn't shared any folder at all; the fix was Properties → Sharing → Advanced Sharing → Share this folder. Another on r/ios fixed it by adding the user to both the Share permissions and the folder's Security (NTFS) permissions. Windows checks both.

5. The iPhone is on a different network

Synology's own help says Files app access over SMB needs both devices on the same local network. Common ways to be on the wrong one without noticing:

Away from home, connect through a VPN back to your network and use the VPN address; Tailscale is one way to do that. Never expose port 445 to the internet.

6. Something specific to one device

In one thread, an iPhone on iOS 18.2.1 failed while an iPad on 18.1.1 connected to the same Mac fine, and nobody found the reason. If you've done everything above, restart the phone, update iOS, and try another device to see whether it's the phone or the server.

Checklist

  1. Use smb:// and the server's home network IPv4 address.
  2. Make sure the address is from the right adapter.
  3. Check SMB is on and port 445 isn't blocked (firewall, network profile, NAS firewall).
  4. On Windows, share a folder and give the account Share and NTFS permission.
  5. Same Wi-Fi as the server, not guest, VPN off at home.

If you get past this and see a different error, try the Files app can't connect to server guide or "Content Unavailable".

Where SMBDrop fits

Disclosure: I make SMBDrop. It's a £9.99 app (one-off, no subscription, no account) that sends photos, videos and files to an SMB share. It talks to the same server on the same port, so everything above still applies: it needs the right IP, an open port 445 and a shared folder just as much as the Files app does. Like the Files app it doesn't scan your network for servers; you type the address, sign in, then Find Shares lists what's shared. Third-party apps, SMBDrop included, also need Settings → Privacy & Security → Local Network turned on, or every connection to your home network fails. If your server uses a non-standard SMB port, SMBDrop lets you set it.

FAQ

What does Socket is not connected mean on iPhone?

Apple doesn't document it, but it often points to an address or network connection problem: the iPhone couldn't reach the SMB service on the address you entered. Common causes are using a computer name instead of its IP address, the wrong IP, port 445 being blocked, or the iPhone being on a different network.

Should I use the computer name or the IP address in Connect to Server?

Use the IP address, for example smb://192.168.1.20. A Mac's .local name also works, but a bare computer name doesn't always resolve from an iPhone, so the IP address is the reliable test.

Is Socket is not connected a wrong password error?

Usually not. In the reports I found, it was fixed by correcting the address, the network or the firewall, which suggests the connection failed before the password was ever checked. Fix those first, then look at the sign-in.

Which port does the iPhone use for SMB?

SMB uses TCP port 445. Synology's firewall guidance also lists ports 137 to 139. Make sure the server's firewall allows them from your local network, and never open them to the internet.

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