Hi Gaspar,
You need to create your BGP process as follow:
router bgp 26XX25
router-id xxx.xxx.xxx.xxx
neighbor xxx.xxx.xxx.xxx remote-as 26XX25
neighbor xxx.xxx.xxx.xxx password m******m0
However, you pinged me over hangout for a private chat and we saw that this password isn't the right one as you're getting a MD5 hash issue coming from your ISP router.
I recommended you to validate with your ISP this password.
Thanks
Francesco
PS: Please don't forget to rate and select as validated answer if this answered your question