If the bot log shows a Severe error during startup it could be because the SAP connectors for Microsoft are missing or not up to date.
The output file on startup will report it as below:
The solution is to go to the SAP support page for Microsoft connectors via the link here.
Then download the 32 bit connector from there and run the installer to ensure that the right connectors are on the bot machine, there is a read me in the folder that you download that you should read an understand for the installation instructions. Note that the bot runs as 32 bit so it is the 32 bit connector that is required.
SAP Connector for Microsoft .NET 188.8.131.52 for Windows 32bit (x86),
If you still have issue then raise a support ticket as per the support section.