GMail IMAP NO [AUTHENTICATIONFAILED] Invalid credentials (Failure)

You passed the correct login/password to login to imap.gmail.com, but you still get an “Invalid credentials” error.  What gives? For example, you called Chilkat’s Imap.Login method, passing the correct login/password, and the imap.LastErrorText contains this: authenticateLogin(110ms): loginImap(110ms): ConnectionType: SSL/TLS ImapCmdSent: aaab LOGIN “you@gmail.com” getCompleteResponse(110ms): ImapCmdResp: aaab NO [AUTHENTICATIONFAILED] Invalid credentials (Failure) –getCompleteResponse –loginImap isOK: serverResponse: aaab NO [AUTHENTICATIONFAILED] Invalid credentials […]

GMail IMAP OAuth2 – A Walkthrough

This blog post covers from start to finish the process for getting a desktop application working with GMail using the IMAP protocol with OAuth2 authentication. Start here:  https://console.developers.google.com/apis/credentials (1) The first step is to create credentials.  Your app is a desktop application.  HOWEVER, you will be creating credentials as if your app is a web app. See this YouTube video […]

O365 IMAP Authentication: OAuth and MFA Solution

There is much confusion and worry about Microsoft’s plans to disable standard password authentication for the IMAP, and POP3  protocols. Here is the announcement posted on 20-Sept-2019 on the Office 365 blog: https://developer.microsoft.com/en-us/office/blogs/end-of-support-for-basic-authentication-access-to-exchange-online-apis-for-office-365-customers/ Chilkat already supports OAuth2 for the IMAP, POP3, and SMTP protocols. (Microsoft will continue to support basic auth for SMTP)  In all three protocols, an application can […]

Email Attachment Info when Downloading from IMAP without Attachments

If the Imap.AutoDownloadAttachments property is set to false, or if headers-only are downloaded, then emails will be downloaded without attachments.  However, attachment information, such as the count, and the size and filename of each attachment is still available. When an email is downloaded from an IMAP server without the attachment data, the attachment information is added as headers to the […]

IMAP: Download email without attachments and downloading attachments separately.

Chilkat version 9.3.0, being released this week, includes new IMAP functionality to fetch emails without downloading attachments, and then subsequently fetch attachments one at a time separately. There is a new boolean property named “AutoDownloadAttachments”, which has  a default value of True (YES).  If set to False (NO), then all Fetch* methods will not download attachments. Note:  “related” items are […]

IMAP: Sequence numbers change when deleting (but not UID’s)

Question: When using IMAP and fetching emails by sequence, does looping through the sequence get affected by deleting in mid-sequence or other changes to the mailbox’s content on the server? Answer: The answer is obtained by examining the IMAP specification (RFC 3501).  Here’s what it says: 2.3.1.2. Message Sequence Number Message Attribute A relative position from 1 to the number […]