Simplenote fails to sync through proxy using custom SSL certificate

[feltech]

At work we must use a system-wide proxy for security scanning. This proxy is a MITM, supplying its own certificate.

With the proxy enabled other apps work OK, and the Simplenote web app works, but the Simplenote Linux app cannot sync. Based on the cert_issuer_source_aia.cc in the stack trace (see below) it looks like the system CAs are not being used.

If I disable the proxy then Simplenote works as expected.

The proxy is configured through Ubuntu's Settings->Network->Proxy UI.

Expected

Notes sync

Observed

Notes permanently have the syncing spinner displayed and don't sync to the server.

$ simplenote --trace-warnings
Checking for beta autoupdate feature for deb/rpm distributions
Found package-type: deb
Error: unrecognized flag --no-expose-wasm
Try --help for options
[654415:0902/111414.870213:ERROR:cert_issuer_source_aia.cc(136)] AiaRequest::OnFetchCompleted got error -301
[654415:0902/111416.678551:ERROR:cert_issuer_source_aia.cc(136)] AiaRequest::OnFetchCompleted got error -301
(node:654415) UnhandledPromiseRejectionWarning: Error [ERR_UNHANDLED_ERROR]: Unhandled error. (undefined)
    at ManualUpdater.emit (node:events:507:17)
    at ManualUpdater.ping (/opt/Simplenote/resources/app.asar/desktop/updater/manual-updater/index.js:82:12)
    at emitUnhandledRejectionWarning (node:internal/process/promises:298:15)
    at warnWithErrorCodeUnhandledRejectionsMode (node:internal/process/promises:406:5)
    at processPromiseRejections (node:internal/process/promises:470:17)
    at process.processTicksAndRejections (node:internal/process/task_queues:96:32)
(node:654415) Error [ERR_UNHANDLED_ERROR]: Unhandled error. (undefined)
    at ManualUpdater.emit (node:events:507:17)
    at ManualUpdater.ping (/opt/Simplenote/resources/app.asar/desktop/updater/manual-updater/index.js:82:12)

Also in journalctl I see lines like the following every few minutes

...
Sep 02 10:48:35 FWTP5313 simplenote.desktop[289829]: [289829:0902/104835.677932:ERROR:cert_issuer_source_aia.cc(136)] AiaRequest::OnFetchCompleted got error -301
Sep 02 10:48:35 FWTP5313 simplenote.desktop[289889]: [289889:0902/104835.678327:ERROR:ssl_client_socket_impl.cc(876)] handshake failed; returned -1, SSL error code 1, net_error -202
...

Where did you see the bug

• System Make: HP
• System Model: Zbook
• OS: Ubuntu
• OS version: 24.04
• Browser (if applicable): NA (Linux app)
• Browser version (if applicable): NA
• Simplenote app version: 2.23.2