I issued three Let’s Encrypt certificates with certbot (two of them were renewed, one is completely new). When I load the page everything works fine. After reloading the site a few times the website throws an SSL Exception: ERR_SSL_PROTOCOL_ERROR (Chrome) / SSL_ERROR_INTERNAL_ERROR_ALERT (FireFox)
When I reload the page again it gets back working sometimes (and sometimes not). This appears for all of the tree domains. Sometimes they work, and sometimes they don’t. I haven’t found any regularity in this behaviour.
It seems as it apache is confused by the setup.
I checked the logs and found the following error code in apache’s error.log:
AH01990: PRNG still contains insufficient entropy!