Pacemaker + Corosync + DRBD + Apache. Fail-over OK, but fail if RJ45 is lost in master

Question

I am testing my cluster, this is the status

iba@iba-master1:/$ sudo pcs status
[sudo] password for iba: 
Cluster name: cluster_iba
Cluster Summary:
  * Stack: corosync
  * Current DC: iba-master1 (version 2.0.3-4b1f869f0f) - partition with quorum
  * Last updated: Wed Mar 24 16:06:11 2021
  * Last change:  Wed Mar 24 15:36:14 2021 by root via cibadmin on iba-master1
  * 2 nodes configured
  * 5 resource instances configured

Node List:
  * Online: [ iba-master1 iba-master2 ]

Full List of Resources:
  * virtual_ip  (ocf::heartbeat:IPaddr2):    Started iba-master1
  * Clone Set: DrbdData-clone [DrbdData] (promotable):
    * Masters: [ iba-master1 ]
    * Slaves: [ iba-master2 ]
  * DrbdFS  (ocf::heartbeat:Filesystem):     Started iba-master1
  * WebServer   (ocf::heartbeat:apache):     Started iba-master1

Daemon Status:
  corosync: active/enabled
  pacemaker: active/enabled
  pcsd: active/enabled

If i make a Fail-over, it's all work OK. The slave take the control. But if I remove the RJ45 connector from the master... it doesn't work properly. In some point my status in the new slave say:

Failed Resource Actions:
  * virtual_ip_start_0 on iba-master1 'error' (1): call=61, status='complete', exitreason='[findif] failed', last-rc-change='2021-03-24 16:30:49 +01:00', queued=0ms, exec=54ms

and after this, the (new) slave can't take control anymore if (new) master fail-over. virtual_ip (ocf::heartbeat:IPaddr2) and WebServer (ocf::heartbeat:apache) was stopped.

these are my constraint list

iba@iba-master1:/mnt$ sudo pcs constraint list --full
Location Constraints:
Ordering Constraints:
  promote DrbdData-clone then start DrbdFS (kind:Mandatory) (id:order-DrbdData-clone-DrbdFS-mandatory)
  start DrbdFS then start virtual_ip (kind:Mandatory) (id:order-DrbdFS-virtual_ip-mandatory)
  start virtual_ip then start WebServer (kind:Mandatory) (id:order-virtual_ip-WebServer-mandatory)
Colocation Constraints:
  DrbdFS with DrbdData-clone (score:INFINITY) (with-rsc-role:Master) (id:colocation-DrbdFS-DrbdData-clone-INFINITY)
  virtual_ip with DrbdFS (score:INFINITY) (id:colocation-virtual_ip-DrbdFS-INFINITY)
  WebServer with virtual_ip (score:INFINITY) (id:colocation-WebServer-virtual_ip-INFINITY)
Ticket Constraints:
iba@iba-master1:/mnt$ 

Any idea what I'm doing wrong? Thanks a lot.