diff --git a/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts b/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts
index 7c1a407c5..6c1ba6e53 100644
--- a/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts
+++ b/packages/backend/src/server/api/mastodon/MastodonApiServerService.ts
@@ -45,6 +45,16 @@ export class MastodonApiServerService {
 			done();
 		});
 
+		fastify.addContentTypeParser(['application/x-www-form-urlencoded'], { parseAs: 'string' }, function (req, body, done) {
+			const dataObj = {};
+			const parsedData = new URLSearchParams(body as string);
+			for (var pair of parsedData.entries()) {
+				//@ts-ignore
+				dataObj[pair[0]] = pair[1];
+			}
+			done(null, dataObj)
+		});
+
 		fastify.register(multer.contentParser);
 
 		fastify.get('/v1/custom_emojis', async (_request, reply) => {