The issue is with the summarization configuration for R1's loopback interfaces. While the summarization is correctly configured, the leak-map used for loopback 50 does not ensure that the loopback address is redistributed into EIGRP.
To successfully advertise all the loopback addresses:
1. Add a network statement for loopback 0: This ensures that the EIGRP process recognizes the loopback interface as part of its routing domain.
router eigrp 100
network 100.1.1.1 0.0.0.0
2. Redistribute the connected route for loopback 50: Since loopback 50 is being referenced in the leak-map, it needs to be explicitly redistributed into EIGRP to be advertised along with the summary route.
router eigrp 100
redistribute connected route-map LOOPBACK50
This configuration ensures:
- The summary route (10.100.1.0/24) is advertised.
- The specific route for loopback 50 (10.100.1.50/32) is leaked through the summary due to the leak-map.

To enable AAA, you need to configure the aaa new-model command in global configuration.
Note: Until this command is enabled, all other AAA commands are hidden.
Warning: The aaa new-model command immediately applies local authentication to all lines and interfaces (except console line line con 0). If a telnet session is opened to the router after enabling this command (or if a connection times out and has to reconnect), then the user has to be authenticated using the the local database of the router. To avoid being locked out of the router, we recommend that you define a username and password on the access server before starting the AAA configuration.
https://www.cisco.com/c/en/us/support/docs/security-vpn/terminal-access-controller-access- control-system-tacacs-/10384-security.html