Occasional "GET .../?/ProxyExternal/...." responded with 500

[module0x90]

2.17.2, Debian package from repository
Vivaldi Linux, 5.4.2753.51

No 500 responses

View particular emails with embedded images

[27-Sep-2022 16:32:54 UTC] PHP Fatal error: Uncaught RuntimeException: Error 28: Resolving timed out after 5000 milliseconds for https://www.vitality.co.uk/media-online/exstream-email-images/Logo_Vitality_HI_Pink.png in /usr/share/snappymail/snappymail/v/2.17.2/app/libraries/snappymail/http/request/curl.php:88
Stack trace:
#0 /usr/share/snappymail/snappymail/v/2.17.2/app/libraries/snappymail/http/request.php(133): SnappyMail\HTTP\Request\CURL->__doRequest()
#1 /usr/share/snappymail/snappymail/v/2.17.2/app/libraries/RainLoop/ServiceActions.php(360): SnappyMail\HTTP\Request->doRequest()
#2 /usr/share/snappymail/snappymail/v/2.17.2/app/libraries/RainLoop/Service.php(133): RainLoop\ServiceActions->ServiceProxyExternal()
#3 /usr/share/snappymail/snappymail/v/2.17.2/app/libraries/RainLoop/Service.php(15): RainLoop\Service::RunResult()
#4 /usr/share/snappymail/snappymail/v/2.17.2/include.php(169): RainLoop\Service::Handle()
#5 /usr/share/snappymail/index.php(11): include('/usr/share/snap...')
#6 {main}
thrown in /usr/share/snappymail/snappymail/v/2.17.2/app/libraries/snappymail/http/request/curl.php on line 88

I have other uncaught RuntimeException where the actual image url doesn't exist, it returns a 404. But the above does exist and I can access the URL in the same browser, as well as download the image from commandline on the same server where SnappyMail is installed.

[the-djmaze]

timed out after 5000 milliseconds

Testing that image, it took between 300ms and 10000 ms before the Incapsula Inc server responded.
As a result, i can conclude their network is terribly slow.

By default all HTTP requests have a timeout of 5 seconds.
You may test a small modification to the code at

snappymail/snappymail/v/0.0.0/app/libraries/RainLoop/ServiceActions.php

Lines 357 to 358 in 1c542b3

	$HTTP = \SnappyMail\HTTP\Request::factory();
	$HTTP->max_redirects = 2;

Into

	$HTTP = \SnappyMail\HTTP\Request::factory();
	$HTTP->max_redirects = 2;
	$HTTP->timeout = 10;

And see if that solves your issue

[module0x90]

Even a timeout = 20 still spits out errors.
I do know that their web presence is grinding slow...
I leave it at the default and simply ignore this error in the logs.

Thank you.