If Windows loses your saved share password after reboot, here are a few things to try:
1. Check Credential Manager. Search for "Credential Manager" in Windows settings and verify that your settings look like this:
If an entry does not exist for your CacheDrive and username, then Windows is not saving the login credentials. If an entry does appear but persistence is set to "Logon Session", then it will only be remembered until the next reboot.
Credentials can also be verified at the command line using:
cmdkey /list
2. If the Persistence setting is set to "Logon Session" and your computer is part of a domain, then try logging in with the following username format:
$domain\$username
3. Domain policies can also affect the ability to save persistent passwords. Contact your network administrator for more information.