UPDATE: A release candidate is available:
If you have trouble with it, please ask for help on their community slack.
There is a patch in the works to add http-01 support to traefik:
If you have an immediate need to obtain/renew certificates you could apply this patch to a local build of traefik.
If you are unable to do that you could also get a certificate with certbot in manual mode or a website like zerossl.com or gethttpsforfree.com and manually configure it with traefik to use until they merge the above patch.
If you need further help, please