Email | XonHost Knowledge Base

How many simultaneous IMAP connections are allowed?

XonHost allows up to 30 simultaneous connections from a single IP. This is the only limitation for IMAP connections and its aim is to prevent security / overload problems. If the number of the allowed connections is exceeded XonHost’s IDS … Continued

The recipient did not receive my email and I did not receive it bounced back

This usually means that the email was caught by a spam filter on the recipient’s mail server. We recommend that you ask the recipient to check the spam / bulk mail folders first. If the message still cannot be found, … Continued

What is CAPTCHA?

CAPTCHA is an acronym for Completely Automated Public Turing test to tell Computers and Humans Apart. It is a type of visual confirmation used in websites to ensure the submission of an entry is not automatically done by a computer/bot. Basically, CAPTCHA is an image with a … Continued

How to disable IDLE processes generated by mail clients

The IDLE function (known as IMAP push) is used by almost every mail client. It allows the IMAP email users to receive any email changes without refreshing their mailbox. In some cases, however, the email client stalls and keeps opening … Continued

Cannot see IMAP folders

In order to resolve this issue first try to subscribe to them. Most email clients have an option similar to “Manage folder subscriptions” where you can subscribe to folders. After the subscription try restarting your mail client and your folders … Continued

Cannot send attachments

You might not be able to send mails with attachments because of: A local antivirus / security application running on your local computer. It might detect that the attachment is either not permitted or is infected by a virus. In … Continued

What is greylisting?

Greylisting is a new popular feature for spam fighting, similar to whitelisting and blacklisting. Each time a mailbox receives an email from an unknown contact (IP), that mail is rejected with a “try again later” message. This means that all … Continued

What is IMAP

IMAP stands for Internet Message Access Protocol and is one of the two most popular protocols for receiving email messages from the Internet, the other one being POP3. The main benefit of the IMAP protocol is that you can access … Continued

My POP3/IMAP server is refusing my connection attempts

The standard server ports used for POP3 and IMAP protocols are 110 and 143 respectively. For a secure connection over SSL/TLS the ports are 995 for POP3 and 993 for IMAP. In case your connection attempts are refused by the POP3 or IMAP server, the most probable cause … Continued

Error: Invalid HELO

The message “invalid HELO command” means that the application you are using for sending mails does not comply with corresponding RFC standards. This happens rarely and the only solution is to use another application for sending mails.