Description
Since the beginning of the year (2025), we seem to have an issue whenever we open Mailspring. Our Public IP Address is automatically blocked by our Email Host (inmotionhosing.com). After a lot of conversation with the technical team at InMotionHosting, we discovered that Mailspring is sending requests without user-agent headers, which raises a red-flag on the hosts side and immediately blocks the IP Address. We make a request to unblock the IP (without closing Mailspring), and we can comfortably use mailspring after this. So this occurs if Mailspring was closed and then restarted (especially in the morning when we boot up our machines).
To Reproduce…
Steps to reproduce the behavior:
- Ensure that Mailspring was fully shutdown. Alternatively, restart a machine.
- Open Mailspring. Mailspring attempts to connect to the server and synchronize emails.
- We receive an error “One or more accounts are having connection issues. Retrying…”
- After requesting for the unblocking of our public IP, Mailspring can download emails and work normally.
Expected Behavior
Mailspring should open and work normally without having connection issues.
Log from Host
Here’s the log sent from InMotionHosting showing, for the most recent occurrence, about 30 minutes before publishing this bug report.
[Thu Jun 05 01:40:36.522735 2025] [security2:error] [pid 2458352:tid 2458488] [client 41.139.192.97:0] ModSecurity: Access denied with code 406 (phase 2). Operator EQ matched 0 at REQUEST_HEADERS. [file “/etc/apache2/conf.d/modsec_vendor_configs/IMH/rules/BASE_RULES.conf”] [line “68”] [id “99111”] [msg “Missing User Agent Header”] [hostname “ngx353.inmotionhosting.com”] [uri “/”] [unique_id “aEFYBNJWENQAAAYE”]
Setup
- OS and Version: macOS 14.7.1
- Installation Method: Installer
- Mailspring Version: 1.15.1