Article ID: kb00096Last Modified: 09-Oct-2026
Error 503 Server Unavailable
| Description | Value |
|---|---|
| Issue ID | 503 (external) |
| Issue Class | Error |
Issue Description
A backup plan fails with the following error message:
Error Message: The remote server returned an error: (503) Server Unavailable
The 503 Server Unavailable error is a response code that means that the target server cannot process the request. This error may occur for several reasons:
- a target server is down for maintenance
- a target server is currently overloaded.
Resolve The Issue
Note that MSP360 (CloudBerry) Backup for Windows automatically handles these errors with retries. Below are log record examples:
2020-01-23 08:42:44,492 [Base] [8] ERROR - Request failed, retrying in 400 msec, 3 attempts left
CloudBerryLab.Base.Exceptions.RequestRateLimitException
The remote server returned an error: (503) Server Unavailable.
2020-01-23 08:42:44,961 [Base] [8] ERROR - Request failed, retrying in 800 msec, 2 attempts left
CloudBerryLab.Base.Exceptions.RequestRateLimitException
The remote server returned an error: (503) Server Unavailable.
2020-01-23 08:42:45,821 [Base] [8] ERROR - Request failed, retrying in 1600 msec, 1 attempts left
CloudBerryLab.Base.Exceptions.RequestRateLimitException
The remote server returned an error: (503) Server Unavailable
If the target server is still unavailable, the backup plan fails. In most cases, these errors are on the storage side.
To Resolve the Issue
Try one of the following options:
- Run the backup plan later
- Contact your cloud storage provider support team regarding possible problems on their side