Delta Force error 4/28: login failed (fix)
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Last checked
September 23, 2026
Login stops on "Login failed, please try again. ID: 4/28" — reported independently across multiple Steam Discussions threads, including players who say it appeared suddenly after previously logging in fine.
Also appears as: delta force error 4/28, delta force login failed 4/28, delta force login failed id 4/28, ID: 4/28, login failed please try again id 4/28
4/28 fits the same login-gate pattern as 4/35 and 5/1200: a corrupted or stale local session-cache file is the most commonly reported cause, and clearing it is the fix players report working most. A smaller number of reports point to a firewall, antivirus, or DNS block preventing the launcher from reaching the login server, which looks identical from the error screen but needs a different fix — try the session-cache reset first since it resolves the error for most reporters.
Fix it, step by step
Delete session.txt in Launcher\Cache\TSF4G2, then log in again
Right-click Delta Force in Steam Library > Properties > Installed Files > Browse. Go to Launcher\Cache\TSF4G2\ and delete session.txt, then relaunch and log in again.
Verify integrity of game files in Steam
Run "Verify integrity of game files" from Steam's Installed Files tab to repair anything the session reset didn't.
Whitelist Delta Force, switch DNS and flush the DNS cache
If it persists, whitelist Delta Force in your firewall/antivirus, then switch your DNS to a public resolver (1.1.1.1 or 8.8.8.8) and run
ipconfig /flushdnsbefore retrying.
Sorted. Glad that worked.
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What people are saying
Notes from players who've hit this one — no time limit, an answer from months ago is still an answer.
- Nothing reported here yet.
From isthisgamedownMatched on ""
From isthisgamedownMatched on ""
From isthisgamedownMatched on ""
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