Neighbor has issue with my tenant

[Winn Vu]

I’m having this tenant that I would want to keep. I self manage. He’s been always paying rent on time and very reasonable to deal with. The lease is going on the 3rd year without any issue until today. My real estate agent called me as a neighbor right behind reached out to her and complained the tenant was having loud parties and such activities that I don’t want to believe. I want to verify the information but don’t know how to approach it with other nearby neighbors. I feel like they would discourage me from leasing the property as they are homeowners. The fist two years I did home inspection and drove by regularly and did not detect any issue. Since the pandemic I postponed my due diligence so I can’t be so sure anymore if the tenant still behaves himself. I can send out just a general reminder of house rules to the tenant but it won’t be very effective if it’s not direct to the point. I also don’t want him to know the neighbor’s complaint until I have verified it. What should I do to keep everyone happy? Thank you for any suggestions and ideas.