Hello! I’ve seen this problem a few times, I think this is caused by a newer change related to Gradle that requires HTTPS:// urls to be used, at the time Forge 1.7.10 was last updated it still used HTTP.

I believe you can fix this by editing the file called “build.gradle” that should be in your mod project’s directory, you can find an example build.gradle file with the fixes here: https://gist.github.com/Arzio/848b8375c4c2ff828d5a7470ac1866b6

(Notice the comments in that example file on lines 1, 6, and 25).