SSL Certificate Error on ios devices

[AKConcept]

Username (e.g. epiz_XXX) or Website URL

akconcept.co.uk
(please specify the website or account you are asking about)
Something Weird Happened yesterday all of the ios Device displayed connection not private error when visiting my website. It shows that the Lets Encrypt Certificate Expired.
I checked my ssl certificate section on Client Area shows that I renewed my certificate last month and its good for next 3 months. Every other devices have no problem. Any one had similar problem??

Error Message

Your connection is not Private
(please share the FULL error message you see)

Other Information

Cleared cache , web browsing history, upgraded to ios 15 , no luck.
(other information and details relevant to your question)

[jaikrishna.t]

There have been some rumours about the let’s encrypt root certificate is expired, don’t know if it is true:

Let’s Encrypts root certificate has expired, and it might break your devices – TechCrunch

For now, using another provider may help. Like: ZeroSSL, GoGetSSL. They’re available to be generated in the client area.

[wackyblackie]

It is true, the DST Root CA has expired. Your cert is most likely using the DST Root CA.