Many companies refuse to acknowledge their certs as legitimate. I worked with some large retailers and they were a no go until the site I was working with had a more recognized cert.
The only thing ...
That must have either been a long time ago, or they must not be using those systems for browsing the web, because LetsEncrypt is like 99% of the "I don't care I just want my website to work" certificates. Including everything I run...
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