High Call Volume: United Airlines, being a major airline, likely has a vast number of customers. There could be periods, especially during holidays, weather disruptions, or flight changes, where many customers are trying to contact the airline simultaneously.
Staffing Levels: Depending on the time of day or specific circumstances, there might not be enough staff available to handle the influx of calls, leading to longer wait times and busy signals.
Technical Issues: Sometimes technical glitches can cause phone lines to appear busy. This could be due to issues with the telecom provider, internal server problems, or other technical disruptions.
Promotions or Changes: If the airline has recently announced a big sale, policy change, or any other significant update, it might cause a temporary surge in calls.
Limitations of the Call System: The phone system infrastructure itself might have limitations on how many concurrent calls it can handle.
If you're facing issues reaching them, you might want to try contacting them through other means like email, social media platforms, or their official website. Additionally, checking their FAQ section might provide answers to some common questions.