For Flashcloud email, use port 465 (SMTP, SSL/TLS) to send and port 993 (IMAP, SSL/TLS) to receive. Username is your full email address, not just the part before the @. If a client asks for POP3 instead of IMAP, use 995. Port 25 and 587 exist too, but they solve different problems, and knowing which is which saves you from guessing when a client's setup screen doesn't match what you expected.
Port 25: mail relay, not your outgoing port
Port 25 is the original SMTP port, used for server-to-server mail relay: one mail server handing a message to another across the internet. It is not meant for an email client (Outlook, Apple Mail, your phone) submitting mail. Most residential ISPs and many cloud networks block outbound port 25 entirely to cut down on spam sent from compromised machines, so if your client is configured to send on port 25, that's usually why mail silently fails to go out.
If you ever see port 25 in a setup screen for your own outgoing mail, switch it to 465 or 587. Port 25 is only relevant to you if you're running your own mail server software and it's relaying to other servers directly, which is not how hosted email works.
Port 465 vs 587: both work, 465 is simpler
These are the two legitimate submission ports for sending mail from a client:
465with SSL/TLS: the connection is encrypted from the first byte. This is what we recommend, and what's covered in full in Email server settings (IMAP and SMTP).587with STARTTLS: the connection starts unencrypted, then upgrades to TLS partway through the handshake. It exists mainly because some older networks blocked 465 but allowed 587.
Both ports work for Flashcloud email. If 465 doesn't connect on a particular network (some corporate or public wifi firewalls are picky), try 587 with STARTTLS instead of assuming your password is wrong. This is worth checking specifically if you're troubleshooting Outlook, since its account wizard sometimes prefills the wrong pairing of port and encryption method.
Port 993: IMAP, the one to use for receiving
Port 993 is IMAP over SSL/TLS. IMAP keeps your mail on the server and syncs read/unread state and folders across every device you check mail from. This is the incoming port you want in almost every case. Set it alongside 465 for outgoing, and both are documented together for each major client in the email server settings reference.
Port 995: POP3, only for specific cases
Port 995 is POP3 over SSL/TLS. POP3 downloads messages to one device and, depending on settings, removes them from the server afterward. There's no sync between devices: read a message on your phone, it still shows unread on your laptop, because each client is downloading its own copy.
Use 995 only if you have a specific reason: you check mail from exactly one device and want to conserve server-side mailbox space, or a piece of legacy software genuinely requires POP3. Otherwise, IMAP on 993 is the better default, and it's what you'll get if you use webmail, since Roundcube and the other webmail clients read the same IMAP mailbox your desktop and phone clients do.
Quick reference
25: server-to-server relay. Don't use it for client outgoing mail; it's frequently blocked anyway.465: SMTP submission, SSL/TLS. Recommended outgoing port.587: SMTP submission, STARTTLS. Fallback if 465 is blocked on your network.993: IMAP, SSL/TLS. Recommended incoming port.995: POP3, SSL/TLS. Single-device, download-and-remove use cases only.
All five expect the same credentials: full email address as username, your mailbox password. See email server settings (IMAP and SMTP) if you're not sure what server address to enter.
When to contact support
If you've matched the right port and encryption method to the right setting and mail still won't send or receive, open a ticket from the portal (Support → New ticket) or use live chat. It helps to mention which specific port and encryption combination you tried and what error message the client showed, since that narrows down whether it's a network block on your end or something to check on the mailbox itself.