LDAP Connection Timeouts

We have OpenFire 3.6.2 running on Windows server 2003 with MSSql as DB and ADAM (on same server) for LDAP since we have multiple AD domains and Spark 2.5.8 as the client. It’s been running fine for several months but recently have seen situations where it starts throwing LDAP connection timeout errors and the system bogs down. Eventually we start seeing Spark connections dropping, search failing, login errors, etc. Rebooting seems to be the only remedy; however, does anyone have an idea what is happening. It’s like ADAM stops responding for some reason.