Your ExpeDat license includes a set limit on the number of simultaneous transactions supportable by each server. Once the capacity is filled, additional transactions will be rejected with the error "Server Capacity Exceeded: Try again later".
Clients requesting file transfer or maintenance operations will automatically retry after receiving a capacity error.
Only active transactions, including file transfers, file maintenance actions, and directory browsing, count toward this capacity. Idle clients do not contribute to the capacity count.
Each MTPexpedat instance may use up to 2 capacity slots at a time: one for an active transfer and a second for browsing or file maintenance. An extra slot may also be used briefly during error recovery when transferring multiple files.
Each DropDat, movedat, and syncdat instance will only use 1 capacity slot at a time. An extra slot may also be used briefly during error recovery when transferring multiple files.
You check the current and peak server loads, as well as the number of "Capacity Exceeded" errors, using the mtping utility, by looking in the logfile for 'S' status lines, or with the Server Dashboard. See the Monitoring section for more about monitoring the server status.
You may reduce the capacity of the server below its licensed limit by using the Capacity configuration variable or the "-c" command line option. This may be desirable if high traffic volumes are creating unacceptable CPU or disk I/O loads, or if you wish to ensure faster speeds for each individual transaction.