One fix for this situation with a caveat, If your IT networking team approves this method (they must ensure that the SSL is being taken care of on the firewall/VPN...), is to add a custom OpenSSL configuration f file and point your system to it. This tells your python to not be concerned about the secure SSL renegotiation (essentially working in a similar fashion as previous ArcGIS Pro and ArcGIS desktop python environments).
The example below is for windows and will enable the ArcGIS Pro 3.0.2 and ArcGIS Pro 3.0.3 (and maybe more into the future) python environments to be able to communicate over https. This example assumes you are a non-admin user putting this fix in place for yourself and not for all users.
1. Create a plain text file at some path on your computer which will not change. You could place it somewhere like: C:\Users\your_username_here\AppData\Local\ssl\openssl.conf
The contents of this file are as follows:
openssl_conf = openssl_init
[openssl_init]
ssl_conf = ssl_sect
[ssl_sect]
system_default = system_default_sect
[system_default_sect]
Options = UnsafeLegacyRenegotiation
2. Now you need to point your system to this file. This is done by adding a user level windows environment variable. You can use the following command in a windows command prompt to do this (edit this command to point to your .conf file.).
setx OPENSSL_CONF C:\Users\your_username_here\AppData\Local\ssl\openssl.conf
Close the command prompt and all ArcGIS Pro, Jupyter Notebook, and Python windows. Then you can open ArcGIS Pro and use some python to initiate an https connection.
for example:
import requests
url = 'https://maps.arcgis.com/index.html'
response = requests.get(url)
print(response.headers)
If you don't get the SSL: UNSAFE_LEGACY_RENEGOTIATION_DISABLED error, but instead have the headers printed, you are good to go.
Another example (assuming you are logged into your ArcGIS Online portal in Pro already):
import arcgis
gis = arcgis.GIS("Pro")
print(gis.users.me.username)
Again, if you do not see the errors and do see your username printed, you are good to go.
Warnings: Please check with your IT department that this is an approved method for your company. You may be opening yourself and your company up to all sorts of cyber security issues.
This fix should not be used unless absolutely required. If your ArcGIS Pro python environment is currently able to negotiate https connections, then you should not implement this fix.
There may be other options for getting the ArcGIS Pro python environment working, but this is the simplest that I have found which enables the default python environment to work without cloning and patching in some other way. Your milage may vary. This has been tested on a computer which has no other python environments and no other ESRI software (no ArcMap). I cannot guarantee this fix would not negatively affect those python environments.
Farley