I am getting a repeatable error when trying to upload files to an extSD card through Airdroid Web.

Client: Airdroid v3.2.2
Phone Model: Samsung Galaxy S7 Edge
Phone OS: Android 6.0.1 (not rooted)
Desktop Browser and OS: Windows 10, Google Chrome 50.0.2661.102
The steps to reproduce this are:
1) Download and install the AirDroid app on my android smartphone
2) Run AirDroid app. Log in using my AirDroid account.
3) On a PC, go to AirDroid Web to connect to my phone.
4) I am asked / forced to select the extSD path on my phone. I do so (AirDroid app --> Files --> External SD. Select the root directory of the extSD card).
5) I can then successfully upload to my extSD card using AirDroid Web.
However, after rebooting my phone and re-connecting to my phone in the future via AirDroid Web gives me the error reported at the top of this post. I can workaround this issue by going into the AirDroid app --> Clear Data + Cache. This forces me to run through Steps 2-5 again, and I can successfully upload.
Any information on how to resolve this issue, without having to go through the Clear Data + Cache workaround every time?
For what it's worth, the last time I experienced this issue was about 1 year ago, using a Samsung Galaxy S5.
http://forums.airdroid.com/viewtopic.php?f=3&t=16421
Since that time, I had been using a Moto X Pure, which did NOT have this issue. This issue only started re-appearing again after I recently switched to a Samsung Galaxy S7 Edge.

Client: Airdroid v3.2.2
Phone Model: Samsung Galaxy S7 Edge
Phone OS: Android 6.0.1 (not rooted)
Desktop Browser and OS: Windows 10, Google Chrome 50.0.2661.102
The steps to reproduce this are:
1) Download and install the AirDroid app on my android smartphone
2) Run AirDroid app. Log in using my AirDroid account.
3) On a PC, go to AirDroid Web to connect to my phone.
4) I am asked / forced to select the extSD path on my phone. I do so (AirDroid app --> Files --> External SD. Select the root directory of the extSD card).
5) I can then successfully upload to my extSD card using AirDroid Web.
However, after rebooting my phone and re-connecting to my phone in the future via AirDroid Web gives me the error reported at the top of this post. I can workaround this issue by going into the AirDroid app --> Clear Data + Cache. This forces me to run through Steps 2-5 again, and I can successfully upload.
Any information on how to resolve this issue, without having to go through the Clear Data + Cache workaround every time?
For what it's worth, the last time I experienced this issue was about 1 year ago, using a Samsung Galaxy S5.
http://forums.airdroid.com/viewtopic.php?f=3&t=16421
Since that time, I had been using a Moto X Pure, which did NOT have this issue. This issue only started re-appearing again after I recently switched to a Samsung Galaxy S7 Edge.