Hi Andrea,
Thanks for your post. Agreed and summarized the response. Storage Replica being set to "synchronous" doesn't mean that your source and destination drives are accessible simultaneously. It means that writes to your source volumes are written to your destination volumes synchronously. Regardless of this, only the active node with the source volumes will have them accessible.
If your destination volumes have become unreachable, that needs to be fixed, preferably before your logs wrap. Otherwise, you may be in for a long resync, depending on how much data you're dealing with.
Best Regards,
Ian Xue
If the Answer is helpful, please click "Accept Answer" and upvote it.