Exchange 2016 DAG unable to seed working database to other servers.

Exchange 2016 DAG unable to seed working database to other servers. After a customer was hacked we had to restore an dold version of the server and import the mail from a copy of the DB on the failover DAG (which also had to be restored, it was the RYUK ransomware team who did a proffesional number on them). now this worked to an extent, the other DAG's are fine and work great but this one will never seed and is shut down with "Error: Communication was terminated by server 'BG-EX-London': Data could not be read because the communication channel was closed". Ive disabled AV etc but it never goes for more than a few seconds.

One clue which I think is the crux here is the database will not mount on its own, I need to manually mount it with the -Force switch before it goes live. Without the Force swithc the error is "Error: An Active Manager operation failed. Error: The database action failed.
Error: Database 'DB1' on server 'Server1' cannot be mounted due to a previous error: At '03/01/2019
09:09:05' the Exchange store database 'DB1' copy on this server appears to be inconsistent with the active
database copy or is corrupted."

So it seems it thinks the other version of the DB is the one that should be live even after Ive removed the DAG copy of it.

Any ideas, this is the only thinhg annoying me after the hack?
LVL 14
plug1Asked:
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AmitIT ArchitectCommented:
It seems db corruption issue. If DB is accessible, better you create new DB and move all mailboxes to new db. Then add the replica for new db. And get rid of old DB.

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plug1Author Commented:
Amit Ive ran a hard repair on the DB using ESEutil and it came back fine so I dont think thats the case.
Valentina PerezExchange ServersCommented:
Hi,

Maybe one option is to create a new database. Move the mailboxes to the new database and after add to the DAG.

How many mailboxes are hosted in the database?

Regards
Valentina
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plug1Author Commented:
It does sound like an option although Id like to fix the current one if possible. there's around 50 mailboxes on it so that would take some time.
AmitIT ArchitectCommented:
As you mentioned, your db is not mounting without force switch. Hence, best option is to move to new DB and discard this db. Easy and fast way.
plug1Author Commented:
When you put it like that, I'll just check that just now :)
Valentina PerezExchange ServersCommented:
Perfect. Thank you for your reply
PRADIIP SINGHCommented:
Did you try to update it using the  _deleteExisting copy switch? both the servers in same site?
plug1Author Commented:
Both in 2 different sites, didn't come across that switch in my googles but I did remove the copy and delete any remains to it..
PRADIIP SINGHCommented:
-DeleteExistingFiles  this is  the switch , give a try also restart the replication service on both the nodes,

or

1- Remove the copy
2- Restart the Replication service
3- Add the copy and see
plug1Author Commented:
Creating the new DB and moving the mailboxes as suggested above seems to be going through tbh so hopefully this will be fine in  a day or so. I'll keep this posted though.
PRADIIP SINGHCommented:
Indeed that should work!
plug1Author Commented:
Just an update that creating the new DB and DAG and migrating the mailbox's worked a treat. All sorted after a stressfull time from the initial hack. Thankyou. Well worth renewing my membership on here for!
AmitIT ArchitectCommented:
Thanks :)
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