Netflix error code F7355-1204 and F7363-1260
Solution 1:
You need to install codec (copy and paste in the terminal).
sudo apt install ubuntu-restricted-extras
Also, a browser extension may be causing the problem, try disabling them.
Solution 2:
Clear your Firefox (version 52 or higher only) caches by going to Preferences, Advanced, Network tab, and click the Clear Now buttons, shown below...