@griffin, thanks a lot for your reply.
Unfortunately deleting with certbot delete didn't work as you can see in the logs below. I was able to delete another cert that I had not manually deleted files from just fine, so it does not look like an argument problem. Instead, this seems to be a long-known bug? Messing with /etc/letsencrypt leads to An unexpected error occurred. TypeError: coercing to Unicode: need string or buffer, NoneType found. · Issue #1195 · certbot/certbot · GitHub
Would you say the work around mentioned here is appropriate?
[douglas.r@certbot-node ~]$ sudo certbot-auto delete --cert-name {DOMAIN}
Your system is not supported by certbot-auto anymore.
certbot-auto and its Certbot installation will no longer receive updates.
You will not receive any bug fixes including those fixing server compatibility
or security problems.
Please visit https://certbot.eff.org/ to check for other alternatives.
Saving debug log to /var/log/letsencrypt/letsencrypt.log
An unexpected error occurred:
TypeError: coercing to Unicode: need string or buffer, NoneType found
Please see the logfiles in /var/log/letsencrypt for more details.
2021-04-06 23:58:42,509:DEBUG:certbot._internal.main:certbot version: 1.6.0
2021-04-06 23:58:42,510:DEBUG:certbot._internal.main:Arguments: ['--cert-name', '{DOMAIN}']
2021-04-06 23:58:42,510:DEBUG:certbot._internal.main:Discovered plugins: PluginsRegistry(PluginEntryPoint#apache,PluginEntryPoint#certbot-route53:auth,PluginEntryPoint#dns-route53,PluginEntryPoint#manual,PluginEntryPoint#nginx,PluginEntryPoint#null,PluginEntryPoint#standalone,PluginEntryPoint#webroot)
2021-04-06 23:58:42,603:DEBUG:certbot._internal.log:Root logging level set at 20
2021-04-06 23:58:42,604:INFO:certbot._internal.log:Saving debug log to /var/log/letsencrypt/letsencrypt.log
2021-04-06 23:58:42,606:DEBUG:certbot._internal.storage:Removed /etc/letsencrypt/renewal/{DOMAIN}.conf
2021-04-06 23:58:42,606:DEBUG:certbot._internal.log:Exiting abnormally:
Traceback (most recent call last):
File "/opt/eff.org/certbot/venv/bin/letsencrypt", line 11, in
sys.exit(main())
File "/opt/eff.org/certbot/venv/lib/python2.7/site-packages/certbot/main.py", line 15, in main
return internal_main.main(cli_args)
File "/opt/eff.org/certbot/venv/lib/python2.7/site-packages/certbot/_internal/main.py", line 1353, in main
return config.func(config, plugins)
File "/opt/eff.org/certbot/venv/lib/python2.7/site-packages/certbot/_internal/main.py", line 1005, in delete
cert_manager.delete(config)
File "/opt/eff.org/certbot/venv/lib/python2.7/site-packages/certbot/_internal/cert_manager.py", line 94, in delete
storage.delete_files(config, certname)
File "/opt/eff.org/certbot/venv/lib/python2.7/site-packages/certbot/_internal/storage.py", line 346, in delete_files
os.remove(link)
TypeError: coercing to Unicode: need string or buffer, NoneType found
2021-04-06 23:58:42,608:ERROR:certbot._internal.log:An unexpected error occurred:
2021-04-06 23:58:42,608:ERROR:certbot._internal.log:TypeError: coercing to Unicode: need string or buffer, NoneType found