Hi,
are you using the integration framework of SAP Business One?
It is based on a tomcat web server using the default http port 8080 and the https port 8443.
If another application like IIS is blocking these ports this could lead to conflicts.
A change of the operating ports of the integration framework according to SAPNote 1618978 - Troubleshooting integration framework installation and upgrade might solve your issue.
Best regards
Bastian