Follow these steps to link your Fastmail account with Warmup Inbox.
Select Email Provider: SMTP & IMAP
SMTP Settings for Fastmail:
SMTP Username: {{your full email address}}
SMTP Password: {{your password to login}}
SMTP Host: smtp.fastmail.com
SMTP Port: 465
TLS: TRUE/YES
IMAP Settings for Fastmail:
IMAP Username: {{your full email address}}
IMAP Password: {{your password to login}}
IMAP Host: imap.fastmail.com
IMAP Port: 993
TLS: TRUE/YES