Invalid Credentials: Unable to receive or send email with basic authentication in FME Flow

Introduction

FME Flow supports the IMAP email protocol in Automations (and Notifications). When configured, FME Flow can monitor an external mail server for incoming emails.

FME Flow and FME Form support the SMTP email protocol in Automations (and Notifications) and the Emailer transformer, respectively. When configured, FME can send emails from this account.

For enhanced security, some email service providers are announcing that third-party applications will no longer be able to sign in using basic username and password credentials for the IMAP and/or the SMTP protocols. You may receive the error "Invalid Credentials" or, in the case of Google, similar errors like "535-5.7.8 Username and Password not accepted". For FME Flow, the only error shown may be "Invalid Parameters", but using developer tools will reveal the full error.  

These changes will impact any version of FME, and if you are using basic authentication in any existing workflows, you’ll encounter an invalid credentials error. To resolve this issue, you’ll need to update your workflow based on the email provider's recommendations:

• Google
• Microsoft

Google 

As of May 1, 2025, Google no longer supports third-party apps or devices that ask you to sign in to your Google Account using only your username and password [More information]. 

To receive/send emails from a Gmail inbox/Google account using FME, the password should be updated to use an app password. When using an app password, do not include spaces.
 

Microsoft

As of October 1, 2022, basic authentication will be disabled for the IMAP protocol. Tenants will be allowed to re-enable a protocol once between October 1, 2022, and December 31, 2022 [More Information]. SMTP authentication will still be available, but if not already in use will be disabled by default. 

Support was added for modern authentication in the Emailer transformer for package version 3.2.0 and is available for download from FME Hub. 

The FME Flow Automations/Notifications IMAP and SMTP protocol, as well as System Email configurations, support the modern authentication method for 2022.2 and newer. 

A patch containing this enhancement has been created for FME Flow 2022.1 b22576+. Should you require this patch, please contact Safe Software Support. 

Note: This patch is not applicable to all versions due to library dependencies. If you are using an older version of FME Flow, you will need to upgrade FME Flow in order to continue using the IMAP protocol.