diff --git a/matrix_puppeteer_line/db/stranger.py b/matrix_puppeteer_line/db/stranger.py
index 72e9e06..5de8a2e 100644
--- a/matrix_puppeteer_line/db/stranger.py
+++ b/matrix_puppeteer_line/db/stranger.py
@@ -61,7 +61,7 @@ class Stranger:
     async def get_by_profile(cls, info: 'Participant') -> Optional['Stranger']:
         q = ("SELECT fake_mid, name, avatar_path, available "
              "FROM stranger WHERE name=$1 AND avatar_path=$2")
-        row = await cls.db.fetchrow(q, info.name, info.avatar.path)
+        row = await cls.db.fetchrow(q, info.name, info.avatar.path if info.avatar else "")
         if not row:
             return None
         return cls(**row)
diff --git a/puppet/src/contentscript.js b/puppet/src/contentscript.js
index e6bd6e9..b73a34a 100644
--- a/puppet/src/contentscript.js
+++ b/puppet/src/contentscript.js
@@ -248,7 +248,7 @@ class MautrixController {
 					.find(e => e.innerText == sender.name)
 				if (participantNameElement) {
 					imgElement = participantNameElement.previousElementSibling.firstElementChild
-					sender.id = imgElement.parentElement.parentElement.getAttribute("data-mid")
+					sender.id = imgElement?.parentElement.parentElement.getAttribute("data-mid")
 				}
 			} else {
 				imgElement = element.querySelector(".mdRGT07Img > img")