The decline outpaced a modest 0.2% drop in S&P 500 futures.Revenue Falls ShortADTRAN expects preliminary second-quarter revenue of $280 million to $282 million, below the $283 million to $303 million prior guidance range and the $293.39 million analyst estimate.The preliminary range trails the consensus estimate by approximately $11.39 million to $13.39 million.Non-GAAP operating margin is expected between 3.5% and 4.0%, below the company’s previous guidance of 5.0% to 9.0%. GAAP operating margin is projected between negative 3.2% and negative 4.0%.The company expects a GAAP loss of 12 cents to 14 cents per share and non-GAAP earnings of 3 cents to 5 cents per share.The non-GAAP range falls well below the 12-cent analyst estimate and compares with break-even earnings a year earlier.Customer Delay WeighsCEO Tom Stanton attributed the weaker results to a project delay involving one customer and elevated component and freight costs."Our preliminary second quarter results were directly impacted by a project delay from a single customer. In addition, margins reflected the current elevated component and freight cost environment," Stanton said.Stanton said the near-term pressures do not alter ADTRAN’s underlying business, customer engagement or strategic priorities. He also pointed to continued strength in optical networking, customer opportunities and an expanding innovation pipeline.Third-Quarter OutlookFor the third quarter, ADTRAN expects revenue of $275 million to $295 million, below the $300.31 million analyst estimate.The midpoint of the range, $285 million, is about $15.31 million below consensus. ADTRAN also expects a non-GAAP operating margin of 1.5% to 5.5%.ADTRAN is scheduled to announce its full second-quarter results on August 3, 2026.ADTN Technical Outlook: Momentum Weakens Below Key AveragesADTRAN trades 19.8% below its 20-day SMA of $12.96, 29% below its 50-day SMA of $14.65 and 9.8% below its 200-day SMA of $11.54. The setup points to broad technical weakness, with the stock trading below all three key moving averages.The $10.50 level is the first resistance test for any rebound, while $9.00 is the key downside support if selling pressure continues.Momentum remains bearish. The MACD is below its signal line and the histogram is negative, indicating weakening buying pressure. Although the stock formed a golden cross in February, its move back below the 200-day average has reduced the strength of that signal.Analyst Consensus & Recent ActionsThe stock carries a Buy rating with an average price forecast of $18.67. Recent analyst moves include: