Many times when the Windows system is updated, some services that are automatically started by the system by default will be turned off, so that we may not be able to use certain tools when we use them. Some of Oracle's services are good examples.
In the morning, when I started pl/sql login as usual, it gave me the error "The listener currently does not recognize the service requested in the connector".
I checked online, and it is recommended to reconfigure the listener in the (Oracle) net manager (delete the address and then re-add the address). After doing so, I found that this problem still cannot be solved.
Then WIN+R, enter services.msc to call out the service, and find that the OracleServiceORCL service is in a closed state. After startup, it is perfectly solved. I will share it here, hoping to help you.