Hello there!
You might have made a typo, it should be RTN 950A.
Please be aware that there are some limitations about PLA, such as:
1. the slave port should be idle (not used by any ETH service) and port mode should be layer 2;
2. the IF boards (two single-IF boards) that provide the master and slave ports for a PLA group must be installed in paired slots and dual-IF boards ISM6 can only support intra-board PLA that consists of its two IF ports;
3. the members in a PLA group must use the same channel spacing;
4. the members in a PLA group must transmit the same type of IF services.
Please check if these requirements are met. And it's recommended to use EPLA if the equipment on both ends of the link supports it.