Self-explanatory notice implementation for sending gateways' credit limit

[mazharulrobeen]

weMail usages third-party gateways for the sending part that's why very often we may encounter some uncleared message that doesn't explain that due to the gateways credit limit crossed we have encountered such notices.

In these cases, it will be very useful for us as users if those notices can be self-explanatory. So, that we can get a clear idea of it.