Why I got "The listing was locked by another process."?

“The listing was locked by another process. Please try again later” means that there’s some listing activity performing at the moment. So this listing is locked and it is not possible to perform any action on it until the current activity is finished.

 You should just wait and try again later as it's said in the message.

Usually this situation happens when automatic synchronization is performed on the listing and you're trying to perform some action at that moment as well.

 
Please let us know if you find this information inaccurate