'Can't complete SOCKS5 connection'
Likely causes
- - Credentials in the wrong flag (-U vs URL)
- - Remote DNS flag mismatch
Verified remedy
Use --socks5-hostname host:port -U user:pass for remote DNS with auth, and retest.
Proxy troubleshooting
Fix curl socks5 greeting failure
Ranked causes, ordered diagnostics, and a verified remedy for curl socks5 greeting failure - ending with a final connection check.
Quick answer
Fix: curl cannot complete the SOCKS5 connection. Confirm endpoint values, test with curl through the endpoint, apply the matched remedy, then re-verify the exit IP is your assigned endpoint.
Exact symptom text
Causes ranked by likelihood
Ordered diagnostics
Final connection check
When this is the right fit
- Exact symptom text
- Causes ranked by likelihood
- Ordered diagnostics
Who this page is for
Ranked causes, ordered diagnostics, and a verified remedy for curl socks5 greeting failure - ending with a final connection check.
Fix: curl cannot complete the SOCKS5 connection. Confirm endpoint values, test with curl through the endpoint, apply the matched remedy, then re-verify the exit IP is your assigned endpoint.
Diagnosis tree
Works with http proxy, fails socks5
Likely causes
- - Endpoint protocol mismatch
- - SOCKS blocked locally
Verified remedy
Confirm the endpoint supports SOCKS5 and test from another network to rule out local blocks.
Final connection check
- 1Apply the remedy for the matched symptom
- 2Test the endpoint directly with curl -x or --socks5-hostname
- 3Repeat the original action in the tool
- 4Confirm the exit IP is the assigned endpoint
Working connection
The original action completes and the exit IP matches the endpoint.
Broken connection
If curl through the endpoint also fails, the problem is endpoint-level: check dashboard status or swap to a spare endpoint.
Sources
Facts last reviewed 2026-09-01.
Prevent it recurring
curl separates proxy auth (-U) from target auth; SOCKS5 hostname form also moves DNS to the endpoint.
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Frequently asked questions
How do I fix curl socks5 greeting failure?
Work the diagnosis tree top to bottom: confirm endpoint values, test with curl through the endpoint, apply the remedy, then run the final connection check.
Why does this keep coming back?
Recurring proxy failures usually trace to an unstable mapping - rotating endpoints or shared addresses. A dedicated static endpoint per profile makes behavior predictable.
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