Looks like it's a bug: http://pietervanhove.azurewebsites.net/?p=1151

Ok, just tried it. I get the same thing. Will keep looking.

DP

Shushing an adult in the workplace is extremely disrespectful.

I prefer to have it so that the service account is granted the rights as described by Sue_H, rather than pre-staging them.

It depends on what 3rd party tool it was. You should theoretically be able to restore a 3rd party Full backup with norecovery followed by however many native transaction log...

Have you definitely enabled TCP/IP on the instance? It's disabled by default on 2014 (?) onwards. The setting can be enabled via SQL Server Configuration Manager.

I'm sure you've tried this already, but have you tried explicitly granting permissions (to the service account) to the folder containing the output file? Or have you compared its permissions...

First things first, have you created an Availability Group listener, and does it work for read/write connections?

For read-only connections you do need to specify the application intent in...

I posted a suggestion above.

Yes. Or you can set it so that whenever either A or B is the primary, the other one is read-only, so they can fail over quite happily with minimal...