A client reported the following error when trying to access the Dynamics GP web client:
The first thing I checked was the event viewer which highlighted the following error in the system log:
I then checked through the system log and found this first starting happening 4 days ago which coincided with a server reboot.
As I knew nothing had changed with the GP environment I asked the clients IT department if any maintenance or other changes had occurred prior to the reboot and they informed me they had disabled both SSL v2 and SSL v3, TLS 1.0 and TLS 1.1.
I knew the issue had to be related to these changes however as this isn’t my area of expertise I called on the assistance of a colleague who after researching themselves advised me to add the following reg keys via an elevated command prompt
reg add HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 /v SchUseStrongCrypto /t REG_DWORD /d 1 /reg:32 reg add HKLM\SOFTWARE\Microsoft\.NETFramework\v4.0.30319 /v SchUseStrongCrypto /t REG_DWORD /d 1 /reg:64
I then recycled the application pool in IIS and restarted all web client related service and this now works.
To confirm the server operating system was Windows Server 2012 R2 and they are using Dynamics GP 2016.
Hope this helps someone else facing a similar issue in future.
Thanks for reading.