Unity 2018.2.21 iOS Build Stuck in xCode

I have a project that has to remain in Unity 2018.2.21 because one of the plugins doesn’t work with anything later yet.

It was building fine not long about, but now when I build in Xcode it gets stuck when it is almost done. I have a new MacBook Pro and the fan is going full speed the whole time.

I have tried a clean build and also in Unity replacing the whole build. Nothing seems to help.

I have the latest Xcode and also several other versions of Unity using Unity Hub including 2019 Unity.

How can I figure out why it is getting stuck?

Well, the creator of the plugin I am using upgraded to the 2018.4 LTS version, so I switched to that and everything seems to work fine. Not sure what the problem was.