Since last week, I've been facing connectivity issues to certain applications.

• I can't make calls and video calls via WhatsApp outside the network, but I can send messages.
• I can't join a discord voice call, but I can send messages. 
• I can't activate an OpenVPN that I need to access external servers.
• Can't even make a speed test at https://www.speedtest.net/

I usually reboot the router and I've already done a factory reset, where I managed to mitigate these problems for a few moments, but they started happening again. Was it some firmware update that is blocking something related to this (some port)?