A month ago I made a wrong manipulation in the Network settings of my computer and since then I cannot browse any websites nor use the Mail app when I connect to my office’s WiFi or at the local café. There, I need to connect to my phone’s 4G in order to browse and check my emails normally, which obviously consumes a lot of data. Another way to be able connect there is to use a VPN. But without the VPN activated, I'm unable to connect.
When I am at home, it connects normally. So there is somewhere some incompatibility with other networks. Is it a DNS or proxy problem ? How can I solve this ?
Please help !