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.
Retrieving data ...