I am using QGIS version 3.4.1. Recently, I cannot install new plugins. I have looked in the plugin setting. It seems that the link is blocked. The address is "https://plugins.qgis.org/plugins/plugins.xml" and it is directed to the "QGIS Python Plugins" website.
In the log Messages I have this warning "WARNING: Failed to load C:/PROGRA~1/QGIS3~1.4/apps/qgis/plugins/grassplugin7.dll (Reason: Cannot load library C".
I have a proxy from my university, disabling the automatic configuration script did not solve the problem.
Also, re-installing QGIS did not help. What else should I look into in order to enable the plugin link?