Navigate to about:config. Paste network.http.connection-timeout in the search bar. The default value is 90 seconds. You can either change it to a longer duration by double-clicking on the value as seen in the image. Or if you just want the extend the timeout duration of the retry attempts, repeat the process for network.http.connection-retry-timeout and change it instead. As of April 2020, there is no way to disable the timeout setting in Firefox or Chrome.

Change network connection timeout settings Firefox

Navigate to about:config.
Paste network.http.connection-timeout in the search bar.
The default value is 90 seconds. You can either change it to a longer duration by double-clicking on the value as seen in the image.
Or if you just want the extend the timeout duration of the retry attempts, repeat the process for network.http.connection-retry-timeout and change it instead.

As of April 2020, there is no way to disable the timeout setting in Firefox or Chrome.