With SonicOS 22.214.171.124 a feature was introduced called TOTP User Authentication. When using this type of authentication via NetExtender or Mobile Connect the SSLVPN connection will drop after about five minutes.
SonicWall developers have successfully identified the issue and a fix is now available. This bug will be permanently addressed in the future 126.96.36.199 release.
Currently SonicOS 188.8.131.52 is not yet published. To request an interim hotfix please contact our Technical Support team and request hotfix (DTS) 215483.
There are two ways to contact technical support:
1. Online: Visit mysonicwall.com. Once logged in select Resources & Support | Support | Create Case.
2. By phone: please use our toll-free number at 1-888-793-2830. Please have your SonicWall serial number available to create a new support case.