After recent Gentoo update I faced GNS3 HTTP communication errors like: Unknown Server error from http://127.0.0.1:8000 Later I found GNS3 branch 1.5 can't reliable communicate when using aiohttp versions above 1.2.0 [1]. In my case dev-python/aiohttp was updated to 1.3.3. I masked aiohttp versions above 1.2.0 and the issue fixed. [1] https://github.com/GNS3/gns3-server/issues/914
A PR has been submitted in bug 618630 for GNS3 2.0.3. I apologize for the package not being maintained. I am working on becoming an active developer again.
bumped. https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=d9ba066b48987853ce08cfd9e2a52c012a3a30d2 This should fix your issue with the new GNS3.