The first step: first check the magnetic charging head of Apple Watch. There is a film on the original film and it has not been torn off. If not, please tear off the film before charging the Apple Watch.
Step 2: Please restart the watch once, and then try to charge the Apple Watch.
Step 3: Check whether the plug part at the other end of the Apple Watch charger is firmly inserted into the socket and loose. Suggest changing a plug to try. It is recommended to use the original charging plug of iPhone to see if you can charge the Apple Watch.
Step 4: There may be something wrong with the charging sensor on the back of the watch. Please check whether there is dirt (sweat and dust) on the charging sensor on the back of the watch. If yes, please clean it with glasses cloth before charging.
Step 5: Find a way to change a magnetic charging cable. There may be something wrong with the charging head or cable (if there is no condition to change, skip to step 6 directly).
Step 6: If the above four steps can't restore normal charging, it may be that there is something wrong with the battery or charging circuit of the watch, so you can only call Apple 400 for after-sales maintenance and let Apple customer service handle it, find out the cause of the failure as soon as possible and strive for warranty.