PostMount
Microsoft 365 mail for apps and devices — problems, fixes and practical guides from the makers of PostMount.
Practical guide
Basic authentication for SMTP AUTH is going away. The errors you’ll see, how to find affected devices, and five ways to keep scanners sending — compared.
9 min read
Sun, Oct 11
Coming soon
Troubleshooting
Fix “535 5.7.139 Authentication unsuccessful, basic authentication is disabled”
What the error means for scanners, ERP and email apps — and the fix that doesn’t re-open basic authentication.
In the works
Coming soon
Comparison
Office 365 SMTP relay: Direct Send vs connector vs local relay
Which relay method fits a small office, a branch on a dynamic IP or a fleet of printers — with the limits of each.
In the works
Coming soon
Guide
Connect an Office 365 shared mailbox to any email app over IMAP
A shared mailbox as a separate account in Thunderbird, The Bat! or a help desk — with its own password and no license.
In the works
Coming soon
Guide
Old Outlook and The Bat! with Office 365 after basic authentication
Outlook 2010–2016 (MSI), The Bat! and other apps without modern sign-in — how to keep them on Microsoft 365.
In the works
Coming soon
Guide
Export an Office 365 mailbox to PST without Outlook or eDiscovery
A full copy with folders and attachments for archiving, offboarding or migration — in PST, MBOX or EML.
In the works
More guides are on the way
SMTP relay, shared mailboxes, legacy email apps, mailbox export — tell us what to cover next.
Suggest a topicIMAP, POP3 and an SMTP relay for Office 365 — without basic authentication.
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