Del.icio.us has been serving an expired SSL certificate since May 4th

Given what the site represents and its current status, this isn't something to worry about. It'll get sorted.

"This project is a labor of love (or more accurately, a labor of like). Del.icio.us was founded by my friends in 2003, sold a whole bunch of times, and when it was about to get sold again to spammers in 2017, I took the opportunity to buy it back.

My current goal is to keep the site up and accessible as a museum of links past.

Right now, all you can really do here is log in and get your old data out."

https://del.icio.us/help