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DNS troubleshooting and common issues

Overview​

DNS issues are the most common cause of domain, CDN, or email problems. This guide helps you identify and fix DNS-related problems quickly.

Common symptoms and fixes​

1) Domain not resolving​

Checks:

  • If you're using Dotsync-managed DNS, verify your domain's nameservers point to Dotsync's nameservers in the registrar dashboard. If you're using a third-party DNS provider, verify the required A/AAAA/CNAME/TXT records are present and correct.
  • Use dig +trace example.com to check delegation and resolution.

Fixes:

  • Update nameservers at the registrar (if using Dotsync-managed DNS) or update the records on your DNS provider, then wait for propagation.
  • Check for DNSSEC misconfiguration.

2) Records not updating or slow propagation​

Checks:

  • Inspect TTL values; high TTLs can delay changes.
  • Confirm that you updated the correct record (A vs CNAME) for the hostname.

Fixes:

  • Lower TTLs before making bulk changes.
  • Re-check cached resolvers; use dig with specific public resolvers (1.1.1.1, 8.8.8.8).

3) SSL validation failures due to DNS​

Checks:

  • Ensure any required validation CNAME or TXT records exist.
  • Verify wildcard certs may require DNS validation.

Fixes:

  • Create the validation record as specified and wait for propagation.

4) CNAME flattening and ALIAS​

If your DNS provider (or Dotsync) performs CNAME flattening or ALIAS behavior, be aware that root/apex domains cannot have CNAME records per the DNS spec. Use A/AAAA or ALIAS records where supported.

Tools & commands​

  • dig example.com +short — quick lookup
  • dig _acme-challenge.example.com TXT — check DNS validation records
  • Online propagation checkers (e.g., DNS Checker)

If problems persist, collect the output of dig commands and contact support with timestamps and the records you expect to see.