Fix only using acme.json in dir

Ref #2978

server/private/lib/acmeCertSync.ts

@@ -500,7 +500,30 @@ function findAcmeJsonFiles(dirPath: string): string[] {
         const fullPath = path.join(dirPath, entry.name);
         if (entry.isDirectory()) {
             results.push(...findAcmeJsonFiles(fullPath));
-        } else if (entry.isFile() && entry.name === "acme.json") {
+        } else if (entry.isFile()) {
+            // check if it is a json file
+            if (entry.name.endsWith(".json")) {
+                let raw: string;
+                try {
+                    raw = fs.readFileSync(fullPath, "utf8");
+                } catch (err) {
+                    logger.warn(
+                        `acmeCertSync: could not read file "${fullPath}": ${err}`
+                    );
+                    continue;
+                }
+
+                let parsed: any;
+                try {
+                    parsed = JSON.parse(raw);
+                } catch (err) {
+                    logger.warn(
+                        `acmeCertSync: could not parse "${fullPath}" as JSON: ${err}`
+                    );
+                    continue;
+                }
+            }
+
             results.push(fullPath);
         }
     }