diff --git a/modules/ai.py b/modules/ai.py
index f613e46..dbeae7d 100644
--- a/modules/ai.py
+++ b/modules/ai.py
@@ -52,8 +52,9 @@ class ResilientModel:
             try:
                 return self.model.generate_content(*args, **kwargs)
             except Exception as e:
-                is_quota = "429" in str(e) or "quota" in str(e).lower()
-                if is_quota and retries < max_retries:
+                err_str = str(e).lower()
+                is_retryable = "429" in err_str or "quota" in err_str or "500" in err_str or "503" in err_str or "504" in err_str or "deadline" in err_str or "internal error" in err_str
+                if is_retryable and retries < max_retries:
                     delay = base_delay * (2 ** retries)
                     utils.log("SYSTEM", f"⚠️ Quota error on {self.role} ({self.name}). Retrying in {delay}s...")
                     time.sleep(delay)
@@ -75,7 +76,7 @@ def get_optimal_model(base_type="pro"):
         if not candidates: return f"models/gemini-1.5-{base_type}"
         def score(n):
             # Prioritize stable models (higher quotas) over experimental/beta ones
-            if "exp" in n or "beta" in n: return 0
+            if "exp" in n or "beta" in n or "preview" in n: return 0
             if "latest" in n: return 50
             return 100
         return sorted(candidates, key=score, reverse=True)[0]
@@ -138,7 +139,7 @@ def select_best_models(force_refresh=False):
         - ARTIST: Needs visual prompt understanding.
         
         CONSTRAINTS:
-        - Avoid 'experimental' unless no stable version exists.
+        - Avoid 'experimental' or 'preview' unless no stable version exists.
         - Prioritize 'latest' or stable versions.
         
         OUTPUT_FORMAT (JSON):