A blinking red light on a Yealink phone typically indicates that there is a missed call or a new voicemail message. The exact meaning of the blinking red light can vary slightly depending on the specific model of your Yealink phone, but in general, it means that there is an important message or notification that requires your attention.

To check your missed calls or voicemail messages, you can follow these steps:

1. Press the "Messages" button on your Yealink phone.
   Use the arrow keys to navigate to the "Voicemail" or "Missed Calls" option, depending on the type of notification that you received.
2. Press the "OK" button to access the list of messages or missed calls.
3. From here, you can view details about the missed calls or voicemail messages that you received and take any necessary actions, such as returning a missed call or listening to a voicemail message.

If you have checked your missed calls and voicemail messages and the red light is still blinking, it's possible that there is an issue with your phone's firmware or settings. In this case, you may want to try resetting your Yealink phone to its default factory settings or contact Yealink technical support for assistance.