I have a cloud service running with a Business tier database.

Have been attempting upgrade to standard via the following:

• Make database copy
• Upgrade database from business to standard

The staging environment works with this upgraded copy at this point, but when I VIP swap production/staging, the database becomes no longer accessible.  My cloud service fails to reach the database, and direct SQL management returns a "failed to create context" error.

I've let it sit for 30 minutes, restarted VM's, but with no success.

I've had firewall issues with SQL Databases where the checkbox to allow Azure IPs to access it doesn't really include all Azure IPs. A work-around that has worked well for us for several years is to add the range: 10.0.0.0-10.255.255.255 and we've not had such a problem any longer.

No clue if this is your problem but it's an easy thing to test. If this is your problem, then it seems to be when they add additional IPs to various data centers but the updating of their firewall rules lag the addition of those IP addresses.