REST Polling Issue

Hi,

I am working on a REST polling scenario means using sender Rest Polling CC. Data is coming as JSON format. Opening the given https url in the web browser I found 3 certificates . All 3 certificates are imported in keystore view TrustedCAs. When I am starting the channel I can see below errors. Please suggest. I have attached some screen shots below -

Error showing in channel -

Ping Error in Channel -

Channel Configuration -

Thanks,