Let's Encrypt certificate for this domain already exists. (Ref. 5008)

[keesskippy]

Hi, I am a newby at certificate management, so please bear with me.
I want to create a new replacement certificate with Letsencrypt for my relatively new domain, but I get the message:
"The Let's Encrypt certificate for this domain already exists. (Ref. 5008)"

Setup: AS6404T-024A, ADM Version 3.4.7.RFO2

Looking on internet sources about Letsencrypt, they suggest this message comes from the NAS software, not from Letsencrypt.
Here is what happened, due to a - for me - unknown reason, my previously setup certificate had the revoked status.
So I tried to replace it, with a new one but that option could not be selected in the interface, so I tried to add a new certificate.
I received the message "The Let's Encrypt certificate for this domain already exists. (Ref. 5008)"
So I'd thought to delete the certificate which seemed to work (it's does not show up and the certificate default from Asustor is there).
However when trying to add a new certificate I am receiving the same message.
I think it is blocked before sent to Letsencrypt, also because the former certificate still seems to be active in internet resources (https://check-your-website.server-daten.de/).

So can anyone help me with this issue?
Maybe I need to delete remnants of the certificate somewhere else?

Thanks very much!
Kees

[orion]

Not sure what's the problem. I'll suggest you to send a support ticket to asustor directly. https://support.asustor.com/

[keesskippy]

Allright Orion, thanks.
I will do so.
Meanwhile, if someone had the same issue (and fixed it), I would be very interested to know..

[keesskippy]

I have an interesting update on this issue, which for me acted as a workaround.
In my domain request to Letsencrypt, I submitted my primary domain, however I also had another domain name in the text field (you can add multiple additional lines there).
(E.g. example.com and www.example.com)
When I switched those lines I all worked!
This strengthens the belief that there are remnants of the old certificate still present (and "indexed" by the original primary domain name) and that there is a check which results in the message "The Let's Encrypt certificate for this domain already exists. (Ref. 5008)"
So while my issue is solved, I still have this problem open with Asustor and half an hour ago I received a reaction requesting for more information.