The connection is using VPN client network Secure VPN establishes correctly and ping works as expected, but the moment the client tries to use HTTP or HTTPS traffic, the remote tunnel drops inexplicably.

• Client can ping other hosts or users in the domain
• VPN client connects with no issues
• Trying to access HTTP or HTTPS drops the VPN
• No logs recorded on the log book of JSC other than the basic disconnection

It's a good practice to check if the IPsec configuration has the following statement:

set security ipsec proposal p2-proposal lifetime-kilobytes "kilobytes"

Possible reason of the issue:

lifetime-kilobytes

Specify the lifetime (in kilobytes) of an IPsec security association (SA). If this statement is not configured, the number of kilobytes used for the SA lifetime is unlimited.

• Range: 64 through 4,294,967,294 kilobytes

If the configuration has a very low amount of kilobytes the connection is expected to drop because of this statement, it is suggested to remove this line unless completely necessary to have on the device, then set the value to a higher number.