Mukesh Verma Root Cause Diagnosis A chargeback stays uncredited when the bank’s internal dispute ticket is marked “raised” or “closed” without a ledger credit, or when the card-network cycle (filing, merchant representment, arbitration) has not finished. Escalations usually fail on admissibility, not merit. The Ombudsman will not take a complaint that skips the bank-first step or misses … Read more
Root Cause Diagnosis The kernel OOM killer selects the process with the highest oom_score, computed as the process’s share of total memory (RSS + swap + page tables) scaled to 0-1000, plus oom_score_adj (range -1000 to +1000). A large, critical daemon such as a database, with a default oom_score_adj of 0, outscores many small processes … Read more
Root Cause Diagnosis The cutter sits 10 to 25 mm below the print head, so the last printed lines have not yet reached the blade when the cut command executes. The ESC/POS cut command GS V 0/1 (full/partial cut) cuts at the current paper position without feeding. Cut commands with a feed parameter (GS V … Read more
Root Cause Diagnosis The “HTTP error” message is the Media Uploader’s generic fallback. It appears when the request to wp-admin/async-upload.php returns anything other than the expected JSON response: a non-200 status, a dropped connection, or a body corrupted by PHP warnings. Failures that occur before WordPress finishes loading are never written to wp-content/debug.log. These include … Read more
Root Cause Diagnosis wait_for_selector times out because the selector either cannot cross the shadow boundary or the element never meets the default state=”visible” condition. Playwright’s CSS and text engines pierce open shadow roots automatically, but they cannot reach closed roots, XPath never pierces shadow DOM, and the > child combinator does not cross a shadow … Read more
Root Cause Diagnosis An authorization hold is a pre-authorization (auth) approved by the issuer that reduces the available balance or credit limit without a financial posting. The hold clears only when the merchant’s acquirer sends a reversal, void, or a clearing/presentment record that matches the original auth (same card token or PAN, auth code, amount … Read more
Root Cause Diagnosis Re-installing the VPS regenerates the SSH host keys in /etc/ssh/sshhost*_key, so the server now presents a different public key from the one your client stored in ~/.ssh/known_hosts on first connection. The client compares the presented key with the stored entry for that IP or hostname, finds a mismatch, and aborts with WARNING: … Read more
Root Cause Diagnosis The tethering session drops when Android or the host OS puts the USB link or the network interface into a low-power state. On Android, Doze, App Standby, and OEM battery managers can suspend the tethering service or the RNDIS/NCM interface when the screen is off and the device is unplugged from a … Read more
Root Cause Diagnosis Orphaned wp_postmeta rows are rows whose post_id no longer matches any ID in wp_posts. They accumulate because wp_postmeta has no foreign key constraint (WordPress tables on MySQL/MariaDB use InnoDB without declared relationships), so any deletion that bypasses wp_delete_post() leaves the meta behind. Typical sources are direct SQL deletes of posts, plugin uninstalls … Read more
Root Cause Diagnosis Turnstile re-issues the challenge when the browser’s signals fail its risk check, so the widget spins or reloads indefinitely instead of returning a token. The usual failing signals are navigator.webdriver === true, a HeadlessChrome user agent, a SwiftShader/software WebGL renderer, missing window.chrome and plugin objects, CDP side effects such as Runtime.enable, and … Read more