I keep a record of the birds I have seen in an Excel spreadsheet. In the cell with the bird name (e.g. Black-throated Trogon) I sometimes insert a hyperlink to a web page. For South American birds I used to use the neotropical.birds pages (e.g. https://neotropical.birds.cornell.edu/Species-Account/nb/species/bittro2/overview). Sometime in 2017 all these links stopped working. I got the error message "Unable to open {url specified}. Cannot locate the internet server or proxy server". I then changed the hyperlinks to the bird forum pages (e.g. https://www.birdforum.net/opus/Black-throated_Trogon). These links worked for a while, but a few weeks ago stopped working. Then I changed to wikipedia (e.g. https://en.wikipedia.org/wiki/Black-throated_trogon). These links worked for a day or two, but now do not work. Same error message.
I have changed the default browser from Safari to Firefox to Opera. Same result.
I have tried using the =Hyperlink() function, as well as copying the url direct from the web page.
I realise from other threads that there may be an issue with some https: sites, but I can't understand why the links were working and then stopped working, without any changes made by me (except perhaps the problem started when I upgraded to El Capitan. But after that the birdforum links were fine until recently).
I have changed the default browser from Safari to Firefox to Opera. Same result.
I have tried using the =Hyperlink() function, as well as copying the url direct from the web page.
I realise from other threads that there may be an issue with some https: sites, but I can't understand why the links were working and then stopped working, without any changes made by me (except perhaps the problem started when I upgraded to El Capitan. But after that the birdforum links were fine until recently).