devliegendebrigade.nl has an AAAA (IPv6) record (2a01:7c8:aaae:5c7::1) but a test request to this address over port 80 did not succeed. Let's Encrypt will prefer to use AAAA records, if present, and will not fall back to IPv4 records. You should either ensure that validation requests to this domain succeed over IPv6, or remove its AAAA record.
Get http://devliegendebrigade.nl/.well-known/acme-challenge/letsdebug-test: dial tcp [2a01:7c8:aaae:5c7::1]:80: connect: no route to host
Trace:
@0ms: Making a request to http://devliegendebrigade.nl/.well-known/acme-challenge/letsdebug-test (using initial IP 2a01:7c8:aaae:5c7::1)
@0ms: Dialing 2a01:7c8:aaae:5c7::1
@3086ms: Experienced error: dial tcp [2a01:7c8:aaae:5c7::1]:80: connect: no route to host
devliegendebrigade.nl has an A (IPv4) record (37.97.128.236) but a request to this address over port 80 did not succeed.
A timeout was experienced while communicating with devliegendebrigade.nl/37.97.128.236: Get http://devliegendebrigade.nl/.well-known/acme-challenge/letsdebug-test: context deadline exceeded
Trace:
@0ms: Making a request to http://devliegendebrigade.nl/.well-known/acme-challenge/letsdebug-test (using initial IP 37.97.128.236)
@0ms: Dialing 37.97.128.236
@10000ms: Experienced error: context deadline exceeded
An internal error occurred while checking the domain
An unknown issue occurred when performing a test authorization against the Let's Encrypt staging service: acme: challenge update timeout