If you have previously verified that your IP was blocked from connecting to your hosting server (is my local IP blocked?) and you are encountering this issue repeatedly, you will need to ensure that the root cause is addressed.
The block of a local IP at any given cPanel server will be incurred for multiple, incorrect access attempts using any protocol - both email (e.g. POP, IMAP, SMTP) and otherwise (e.g. FTP). Blocks will also be incurred for attempts at shell (SSH) access as this is disabled on our servers, or triggering of mod_security (which detects and prevents malicious connection attempts, e.g. specific attacks such as SQL injection).
You will need ensure all users (of emails or other services, such as your web designer) are using correct credentials on all machines, clients, devices etc., and if you have multiple users of services on the same network, ensure they are connecting at reasonable intervals. A blocked IP indicates that one or more users at the blocked location is failing to log-in to authenticated hosting services multiple times in short periods, or connecting with excessive frequency, and is incurring these blocks.
Unless we have confirmed that your IP has been blocked plesae do consider that what you are experiencing may not be a block of your IP. Please check our other FAQ entries such as Why is my domain not working?, Why is my website not working? and Why are my emails not working?