I ran a difference-in-differences model using the command DIFF (Villa, 2016) in Stata/IC 15.1 on a sample of 726 firm-years. The command I used is the following:

diff Y, t(treated) period(post) cov(controls) cluster(ID)

where Y is the dependent variable, post is a dummy equal to one after the event, controls is a set of control variables and standard errors are clustered at firm ID level. I obtain the following output:
DIFFERENCE-IN-DIFFERENCES WITH COVARIATES
DIFFERENCE-IN-DIFFERENCES ESTIMATION RESULTS
Number of observations in the DIFF-IN-DIFF: 726
Before After
Control 230 210 440
Treated 147 139 286
377 349
Outcome var. Y S. Err. |t| P>|t|
Before
Control 0.051
Treated 0.046
Diff (T-C) -0.005 0.003 -1.47 0.147
After
Control 0.053
Treated 0.065
Diff (T-C) 0.012 0.009 1.39 0.168
diff-in-diff 0.017 0.007 2.28 0.025**
R-square: 0.15
* Means and Standard Errors are estimated by linear regression
**Clustered Std. Errors
**Inference: *** p<0.01; ** p<0.05; * p<0.1

My difference after and my difference before are not significant but my diff-in-diff term is. How can I interpret this result ?

I thank you for your help.

References
Villa, J.M., 2016. diff: Simplifying the estimation of difference-in-differences treatment effects. Stata Journal 16, pp. 52-71