When converting to HTTPS canvas page is blank

I have gone through the apparently needed process of purchasing SSL certs etc, and have now changed my URLs for the tabs to https.. however when accessing these there is nothing shown.. blank. Works fine with http.

Can anyone help me o开发者_StackOverflow中文版ut please? Can't find any decent documentation on this.

Thanks

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Did you change the "Canvas URL" to https? "Canvas URL" should be the http url and "Secure Canvas URL" should be https. If you simply change "Canvas URL" to https then it would show a blank page.