Hi there Sniggy,
Is this issue something new that just happened, for example after something from your end changed, or has this been an issue for you from the start?
For most common infinite load issues please take a look at this document here and try to apply the solutions to all of your devices you use to play via Forge.
Additionally, if you have external firewall or anything else that filters your internet traffic please make sure that the Forge domain is whitelisted.
-Aki