Using Electrum via Proxy

[mocacinno]

Your screenshot shows your domain... I realise by the fact that you wiped out your tld in some parts of the screenshot you want to keep this info private, so maybe you can remove the screenshot and replace it by a censored one

This being said, i did visit your domain, and it seems like your tld already has an x3 certificate... Is your btcpayserver located on a subdomain? In this case you have to make sure the correct block exists in your nginx site config and you have to execute:

certbot --nginx -d sub.domain.com

It's the subdomain you want a certificate for in case you installed btcpayserver on a subdomain (like i did).

Now, the error you see seems to be rather common... A quick google resulted in sollutions like this one: https://community.letsencrypt.org/t/solved-the-client-lacks-sufficient-authorization-404-not-found/50894
Apparently, in this case, the posted deleted the AAAA record for his domain to solve the problem, but the post also helps the poster with some initial troubleshooting, you can repeat the steps they told him to do some troubleshooting for yourself

This being said, certbot does not have any authorisation towards your zone editor, it cannot modify dns zones all by itself, i have no idear how those records were entered?
Are you 100% certain you didn't do this? Did you ask support from somebody who is authorised to edit zone record (your hosting company for example?)? Did you give credentials to a thirth party (a partner, a friend)?

[mocacinno]

Isn't Electrum a Bitcoin wallet? Why do you need to connect a proxy to a cryptocurrency wallet? Can you please explain in more detail why a proxy is needed and why it should be connected to a web wallet?

I usually don't have the habit of replying on a thread that's a year old... I usually just report the new post to a moderator and have it removed due to necroposting...
But, it seems you're new to this forum, and your question might not have been completely answered in this thread, so i guess it might be nice to cut you some slack.

You are right, electrum IS a wallet, and it does not HAVE to use the tor proxy. It's fine to run your wallet connecting to clearnet nodes, BUT, those clearnet nodes WILL be able to log your ip and the addresses you request. So, in theory, a node owner will know your ip and part of your unspent outputs... This is why some people prefer extra privacy by running a tor client and using this client as a proxy. By doing this, they hide their ip from the electrum nodes they connect to.
A different sollution sometimes used is running a full node, then installing electrs or electrumx and connecting to your own node... That way you are 100% sure the node owner isn't malicious.

In the future, just as a general rule of thumb: the forum has some rules against necroposting (posting in a thread that hasn't been posted in for a long time), so if you have questions like these, you can open a new thread or PM somebody in the original thread

[HCP]

Isn't Electrum a Bitcoin wallet? Why do you need to connect a proxy to a cryptocurrency wallet? Can you please explain in more detail why a proxy is needed and why it should be connected to a web wallet?

Firstly... Electrum isn't a "web wallet". It's a desktop client (or mobile if you are using the Android version).

Also, the proxy functionality in Electrum is not just for Tor... some folks might be using networks that are being "restricted" or filtered. Sometimes using a proxy server can bypass these restrictions and allow you to connect to the service that you're after, like an Electrum server