diff --git a/scripts/pma-gateway/create_pma_gateway.sh b/scripts/pma-gateway/create_pma_gateway.sh
index a5c0771..8b888bb 100644
--- a/scripts/pma-gateway/create_pma_gateway.sh
+++ b/scripts/pma-gateway/create_pma_gateway.sh
@@ -37,14 +37,37 @@ if [[ "$CONTACT_EMAIL" == *'${'* ]]; then
   CONTACT_EMAIL=""
 fi
 
-# Prefer explicit cert domain and fallback to Jelastic environment domain.
-if [[ -z "$CERT_DOMAIN" ]]; then
-  if [[ -n "${JELASTIC_ENV_DOMAIN:-}" ]]; then
-    CERT_DOMAIN="$JELASTIC_ENV_DOMAIN"
-  else
-    CERT_DOMAIN=$(hostname -f)
-    CERT_DOMAIN=${CERT_DOMAIN#node*-}   # strip nodeXXXX-
+# Build domain candidates in priority order:
+# 1) explicit --cert-domain
+# 2) JELASTIC_ENV_DOMAIN
+# 3) hostname-derived domain
+HOSTNAME_DOMAIN=$(hostname -f)
+HOSTNAME_DOMAIN=${HOSTNAME_DOMAIN#node*-}
+
+DOMAIN_CANDIDATES=()
+SEEN_DOMAINS="|"
+for candidate in "$CERT_DOMAIN" "${JELASTIC_ENV_DOMAIN:-}" "$HOSTNAME_DOMAIN"; do
+  if [[ -n "$candidate" ]] && [[ "$SEEN_DOMAINS" != *"|$candidate|"* ]]; then
+    DOMAIN_CANDIDATES+=("$candidate")
+    SEEN_DOMAINS="${SEEN_DOMAINS}${candidate}|"
   fi
+done
+
+# Never use legacy *.sites.mightybox.dev domains for PMA gateway certificates.
+FILTERED_DOMAINS=()
+for candidate in "${DOMAIN_CANDIDATES[@]}"; do
+  if [[ "$candidate" == *.sites.mightybox.dev ]]; then
+    echo "WARNING: Skipping legacy domain candidate '$candidate' for PMA gateway SSL." >&2
+    continue
+  fi
+  FILTERED_DOMAINS+=("$candidate")
+done
+DOMAIN_CANDIDATES=("${FILTERED_DOMAINS[@]}")
+
+if [[ "${#DOMAIN_CANDIDATES[@]}" -eq 0 ]]; then
+  echo "FATAL: No valid non-legacy environment domain candidate found for PMA gateway certificate resolution." >&2
+  echo "       Provide --cert-domain with the current default environment domain." >&2
+  exit 1
 fi
 
 # Fallback for email when not explicitly passed.
@@ -52,7 +75,7 @@ if [[ -z "$CONTACT_EMAIL" ]] && [[ -n "${JELASTIC_USER_EMAIL:-}" ]]; then
   CONTACT_EMAIL="$JELASTIC_USER_EMAIL"
 fi
 
-ENV_HOST="$CERT_DOMAIN"
+ENV_HOST="${DOMAIN_CANDIDATES[0]}"
 
 PMADB_DIR="/usr/share/phpMyAdmin"
 GATEWAY_FILE="$PMADB_DIR/access-db-$SLUG.php"
@@ -78,30 +101,42 @@ token="$base.$mac"
 VHOST_CONFIG="/usr/share/phpMyAdmin/vhost.conf"
 NEEDS_RESTART=0
 
-# --- Let's Encrypt certificate resolution for ENV_HOST ---
+# --- Let's Encrypt certificate resolution for domain candidates ---
 LE_LIVE_DIR="/etc/letsencrypt/live"
 LE_CERT_DIR=""
+CERT_DOMAIN_USED=""
 
-# Attempt exact match first.
-if [[ -d "$LE_LIVE_DIR/$ENV_HOST" ]] && [[ -f "$LE_LIVE_DIR/$ENV_HOST/privkey.pem" ]] && [[ -f "$LE_LIVE_DIR/$ENV_HOST/fullchain.pem" ]]; then
-    LE_CERT_DIR="$LE_LIVE_DIR/$ENV_HOST"
-    echo "INFO: Found exact Let's Encrypt cert directory: $LE_CERT_DIR" >&2
-fi
+# Find an existing certificate for the first matching candidate.
+for candidate_host in "${DOMAIN_CANDIDATES[@]}"; do
+    if [[ -d "$LE_LIVE_DIR/$candidate_host" ]] && [[ -f "$LE_LIVE_DIR/$candidate_host/privkey.pem" ]] && [[ -f "$LE_LIVE_DIR/$candidate_host/fullchain.pem" ]]; then
+        LE_CERT_DIR="$LE_LIVE_DIR/$candidate_host"
+        CERT_DOMAIN_USED="$candidate_host"
+        echo "INFO: Found exact Let's Encrypt cert directory for '$candidate_host': $LE_CERT_DIR" >&2
+        break
+    fi
 
-# Then try certbot-suffixed directories (e.g., domain-0001).
-if [[ -z "$LE_CERT_DIR" ]]; then
-    for dir in "$LE_LIVE_DIR/$ENV_HOST"-*/; do
+    for dir in "$LE_LIVE_DIR/$candidate_host"-*/; do
         if [[ -d "$dir" ]] && [[ -f "$dir/privkey.pem" ]] && [[ -f "$dir/fullchain.pem" ]]; then
             LE_CERT_DIR="${dir%/}"
-            echo "INFO: Found suffixed Let's Encrypt cert directory: $LE_CERT_DIR" >&2
+            CERT_DOMAIN_USED="$candidate_host"
+            echo "INFO: Found suffixed Let's Encrypt cert directory for '$candidate_host': $LE_CERT_DIR" >&2
             break
         fi
     done
+
+    if [[ -n "$LE_CERT_DIR" ]]; then
+        break
+    fi
+done
+
+if [[ -n "$CERT_DOMAIN_USED" ]]; then
+    ENV_HOST="$CERT_DOMAIN_USED"
 fi
 
-# If no cert exists yet, attempt one-time issuance for ENV_HOST.
+# If no cert exists yet, attempt one-time issuance for highest-priority candidate.
 if [[ -z "$LE_CERT_DIR" ]]; then
-    echo "WARNING: No Let's Encrypt certificate found for '$ENV_HOST'. Attempting to issue one now..." >&2
+    ENV_HOST="${DOMAIN_CANDIDATES[0]}"
+    echo "WARNING: No Let's Encrypt certificate found for domain candidates (${DOMAIN_CANDIDATES[*]}). Attempting to issue one for '$ENV_HOST' now..." >&2
 
     CERTBOT_CMD=""
     if command -v certbot >/dev/null 2>&1; then
@@ -110,6 +145,24 @@ if [[ -z "$LE_CERT_DIR" ]]; then
         CERTBOT_CMD="/opt/certbot/certbot-auto"
     fi
 
+    if [[ -z "$CERTBOT_CMD" ]]; then
+        echo "WARNING: certbot is not available. Attempting to install certbot..." >&2
+        if command -v dnf >/dev/null 2>&1; then
+            sudo dnf install -y --setopt=install_weak_deps=False certbot >/dev/null 2>&1 || true
+        elif command -v yum >/dev/null 2>&1; then
+            sudo yum install -y certbot >/dev/null 2>&1 || true
+        elif command -v apt-get >/dev/null 2>&1; then
+            sudo apt-get update -qq >/dev/null 2>&1 || true
+            sudo apt-get install -y certbot >/dev/null 2>&1 || true
+        fi
+
+        if command -v certbot >/dev/null 2>&1; then
+            CERTBOT_CMD="certbot"
+        elif [[ -x "/opt/certbot/certbot-auto" ]]; then
+            CERTBOT_CMD="/opt/certbot/certbot-auto"
+        fi
+    fi
+
     if [[ -z "$CERTBOT_CMD" ]]; then
         echo "FATAL: certbot is not available and no existing Let's Encrypt certificate was found for '$ENV_HOST'." >&2
         exit 1
@@ -150,6 +203,7 @@ if [[ -n "$LE_CERT_DIR" ]]; then
     LE_CERT_FILE="$LE_CERT_DIR/fullchain.pem"
 else
     echo "FATAL: Let's Encrypt certificate directory could not be found for ENV_HOST: $ENV_HOST" >&2
+    echo "       Checked candidates: ${DOMAIN_CANDIDATES[*]}" >&2
     echo "       Checked specific path: $LE_LIVE_DIR/$ENV_HOST" >&2
     echo "       Checked suffixed paths: $LE_LIVE_DIR/${ENV_HOST}-*" >&2
     exit 1