Hi Everyone,
I have a fairly large environment consisting of 25 APEs and 25 HA APEs. These APEs span across different datacenters across the globe. When attempting to do the centralized upgrade to 2019.4 I am running into an issue on several of the APEs.
The APEs will first state "Downloading installers...2%" along with the KB/s of which it is downloading. But that's where they stop. After several minutes they will fail out with the following error.
An error was encountered while downloading updates:
Can't download file https://downloads.solarwinds.com/solarwinds/CatalogResources/Core/2019.4/2019.4.5220.20161/CoreInstaller.msi, because of the invalid checksum: 38385A81664CE562A6777FA4564AE7B93F38F1224E1206550136E2B6B5DBB9DD for file C:\ProgramData\SolarWinds\Downloads\CORE-2019.4.5220.20161-CoreInstaller.msi
I've already tried to retry the download and the same thing happens.
So I remoted into one of the servers having the issue and pasted the URL from the error message;
and I were able to download it with no problem across the internet.
So on the problem APE I navigated to the file location displayed in the error message;
C:\ProgramData\SolarWinds\Downloads\CORE-2019.4.5220.20161-CoreInstaller.msi
I deleted the file that was currently present and then clicked retry again on the web console. After a few minutes, the file appeared and even though the percentage on the web console stated 2% the file size was growing, slowly but the percentage never changed.
I also verified if I was able to navigate to my Primary Polling Engine from the troubled APE and I was able to with no issues.
All of the 14 APEs that completed the upgrade successfully were in fact located in the same Datacenter as my Primary Polling Engine. So I started checking the latency between the APE and Primary and yes some had some high latency but there were also several that were under 30ms and those also failed.
I am drawing a blank on this and any help would be great 
