In the event that the messages remain in Pending or Sending status, it is possible that some of the filters or security measures of the LabsMobile platform have temporarily held the messages.
Especially the first messages with links or with reserved words will be held until they are validated manually. Validated or high trust accounts (with a history of valid and approved messages) are less likely to be affected by these filters.
These measures are required by the agreements LabsMobile has with the telephone operators and also by the commitment to preserve the SMS channel free from fraud, unwanted messages, abuse, and bad practices.
It is important to check (in the Account settings) the limits of the sending capacity of the account, time filter, anti-duplicates, and others to avoid unnecessary crashes.