docs: Update FAQ.md (#2126)

Co-authored-by: liuxiran <[email protected]>

Author: wjmmjr

docs/en/latest/FAQ.md

@@ -129,3 +129,10 @@ enabled = true
 # grep 'allow_embedding' defaults.ini
 allow_embedding = true
 ···
+```
+
+### 9. APISIX dashboard configured domain name, the embedded Grafana can't login
+
+If the domain name of the address is configured as HTTPS, the embedded grafana will jump to the login page after logging in. You can refer to this solution:
+
+It's best for Grafana to configure the domain name in the same way. Otherwise there will be problems with address resolution.