OAuth Callback Failure: Localhost Port Unreachable on Safari
Resolved 💬 7 comments Opened Jun 3, 2025 by mfazekas Closed Jan 5, 2026
Bug Description
Trying to register linear MCP SSE server. \
\
[DEBUG] MCP server "linear": Authorization URL: https://mcp.linear.app/authorize?response_type=code&client_id=Awe5h3&code_challenge=-F2b**FsuA_lilJk&code_challenge_method=S256&redirect_uri=http%3A%2F%2Flocalhost%3A45123%2Fcallback\
\
MCP server "linear" Error: Unauthorized
[DEBUG] MCP server "linear": Authentication required for SSE server
\
\
Then browser is opened and it tries to redirect to:\
\
http://localhost:45123/callback?code=6f909992-**\
\
But Safari Can't Connect to the Server. Safari cannot open the page "localhost:45123/..." because safari can't connect to server "localhost"
Environment Info
- Platform: macos
- Terminal: vscode
- Version: 1.0.9
- Feedback ID: 0b55da21-ab72-4e90-a5c9-a86f7ebddc82
Errors
[{"error":"SyntaxError: Unexpected token } in JSON at position 50\n at JSON.parse (<anonymous>)\n at s5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:557:9977)\n at jp9 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:307)\n at mH (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:995)\n at l8 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:1336)\n at q50 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:643:6202)\n at file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:693:1493\n at Q (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:526:17069)\n at hF5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2298:17523)\n at file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2302:6238","timestamp":"2025-06-03T11:00:44.635Z"},{"error":"Error: Invalid managed settings: [\n {\n \"code\": \"invalid_type\",\n \"expected\": \"object\",\n \"received\": \"null\",\n \"path\": [],\n \"message\": \"Expected object, received null\"\n }\n]\n at jp9 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:356)\n at mH (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:995)\n at l8 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:1336)\n at q50 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:643:6202)\n at file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:693:1493\n at Q (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:526:17069)\n at hF5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2298:17523)\n at file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2302:6238","timestamp":"2025-06-03T11:00:44.638Z"},{"error":"SyntaxError: Unexpected token } in JSON at position 50\n at JSON.parse (<anonymous>)\n at s5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:557:9977)\n at jp9 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:307)\n at mH (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:995)\n at Ks1 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1406:1489)\n at LF2 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1406:1450)\n at fF5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2298:14429)\n at W1A.<anonymous> (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2298:20806)\n at async W1A.parseAsync (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:517:4184)\n at async dF5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2302:5972)","timestamp":"2025-06-03T11:00:44.733Z"},{"error":"Error: Invalid managed settings: [\n {\n \"code\": \"invalid_type\",\n \"expected\": \"object\",\n \"received\": \"null\",\n \"path\": [],\n \"message\": \"Expected object, received null\"\n }\n]\n at jp9 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:356)\n at mH (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:562:995)\n at Ks1 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1406:1489)\n at LF2 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:1406:1450)\n at fF5 (file:///Users/boga/.claude/local/node_modules/@anthropic-ai/claude-code/cli.js:2298:14429)\n at W1A.<anonymous> (file:///Users/boga/.claude/lNote: Error logs were truncated.
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