Resource exchange request fails

[Angel R]

Steps to reproduce:

1. access to instanceA.service-now.com to one sys_certificate.
2. Click on Validate Stores/Certificates
3. result is Valid pkcs12_key_store
4. Export record as xml then import on instance b.
5. go to record on instance b.
6. Click on Validate Stores/Certificates
7. result is java.lang.Exception: Invalid pkcs12_key_store : keystore password was incorrect

Resource Exchange Requests is configured and approved following those instructions:

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB1122520

meaning, on instance b:

Exchange Frequency: Adhoc (we are doing a once off exchange)
Source Instance Sys Id: You can get this from "stats.do" on "Instance A" (instance which contains the original record).
Source Instance Host: instanceA.service-now.com
Crypto Specifications: com_glide_certificates_glideencrypter (this may differ depending on your results from step 5 of "Finding the Crypto Module")

But the system returns the following error:

Failed to send out the key exchange request, Cannot send over key exchange request succesfully.
Error details, Error Code: REQUEST_HANDLING_ERROR
Crypto Module: <sys_id>, Crypto Spec: <sys_id>, Message Type: KeyExchangeRequest, Resource Owner Instance Id: <sys_id>, Resource Owner Host: instancea.service-now.com, Requester Instance Id: <sys_id>, Requester Host Address: instanceb.service-now.com,Exchange Frequency: AD_HOC
: no thrown error

Any idea how to solve?