Have used Self signed certificate but still not able to login in Collector using Portal URL.
I don't have much context/info to go on, but please review this GeoNet thread, sync error - illegal start of token
Also, this blog post: ArcGIS Collector Illegal Start of Token - Spatial Times
Hope this helps,
The problem is resolved now. Actually we dont have to place "home" in the URL of Portal when we login in the Collector.