If I understand it correctly, according to issue #1607 in the main netbird repository (netbirdio/netbird#1607) there should be a fallback port in case localhost:53000 does not accept callbacks.
Please verify if this is also the case for the android client, one of my users got ERR_CONNECTION_REFUSED for localhost:53000 after completing login with our selfhosted instance.
If I understand it correctly, according to issue #1607 in the main netbird repository (netbirdio/netbird#1607) there should be a fallback port in case localhost:53000 does not accept callbacks.
Please verify if this is also the case for the android client, one of my users got ERR_CONNECTION_REFUSED for localhost:53000 after completing login with our selfhosted instance.