Can anyone offer guidance...

I am flying Copa out of Panama within the next 24 hours. My ticket is a business class RTW on LH stock. A few days ago, I had no problem checking in on Copa.com for an earlier Copa flight on same RTW itinerary.

Mind you, between then and now, I did make a change to a downline flight on the ticket, so the ticket was reissued. But this Copa flight remains the same.

But today, no go for check in. I called Copa, and they said the ticket is fine, and that I should get to the airport 3 hours in advance of my 8 am flight to check in.

3 hours??? Any advice? Would a visit to the local Copa cto help?