ExportWebMapTask Errors out on server

[JayHill]

I'm trying to use the Print widget in the 4.3 JS API.  I get the following errors when I test it out.  

1. Error executing tool. Export Web Map Task Job ID: jf8ec59473f97475a9649aa039c01190b : Layer "Wetland Mapper": Unable to connect to map server at https://map.com/MapServer. Failed to execute (Export Web Map). Failed to execute (Export Web Map Task).

2. A connection with the server could not be established (WinINet Error while using HTTPS security, 12029), URL = https://map.com/MapServer?f=json

3. A connection with the server could not be established (WinINet Error while using HTTPS security, 12029), URL = https://map.com/arcgis/rest/info?f=json

I've tried using the default GP service and a custom one.  Same errors on both.  Also I have tried using http and https

[JYI]

With the great help from ESRI support, it turned out that there are two big issues with this print function:

1. Reverse proxy server configuration.

Since one error is from https://public-url/arcgis/rest/info?f=json, open this link from the browser and check the SOAP url or Token service url. The url does not point to https://public-url domain. Instead, they use the internal server name. 

In the reference https://enterprise.arcgis.com/en/server/10.5/administer/windows/using-a-reverse-proxy-server-with-ar..., it shows that "If the X-Forwarded-Host header property is not set, ArcGIS Server and ArcGIS Web Adaptor may return the URL of the internal machine where the request was directed," which is exactly the part we missed in the Reverse Proxy Server configuration.

https://www.jetbrains.com/help/hub/Proxy-Configuration.html#IIS_Config is the reference for how to Configure the headers of your proxy server in IIS.

2. The ArcGIS Server for https://public-url/arcgis/rest/services/folder/AClassA/MapServer   does not recognize the domain https://public-url. I.e., from a browser in the ArcGIS Server machine, https://public-url/arcgis/rest/services/folder/AClassA/MapServer is not accessible.

This is fixed by adding the ip address of the reverse proxy server and the public-url to C:\Windows\...

[JYI]

Has anyone successfully configured Portal for ArcGIS with Microsoft IIS reverse proxy server to make Portal for ArcGIS publically accessible? I had problem with changing user Password in Portal for ArcGIS 10.5.1, using MS IIS reverse proxy server for public access.  

Everything works fine, except if user trying to change their Password, after pressing Change password button, the url host name goes back to the internal server name, instead of the public domain name. I.e., https://aaawebapp01/arcgis/sharing/oauth2/resetPassword?oauth_state=qYQc9....., instead of https://public-url/arcgis/sharing/oauth2/resetPassword?oauth_state=qYQc9......

It seems to me that as the change password page is a form, the url rewrite rule is not properly recognized and thus the internal server name is in the header.   

Could anybody shed lights on this?  Thanks!

[JYI]

The issues in Configure Portal for ArcGIS with Microsoft IIS reverse proxy server have been solved. See

https://community.esri.com/message/756307-make-portal-for-arcgis-public-accessible-using-iis-reverse... for the solution.