Model not completing the chains running

fit_DriversWTA_CFC5 ← brm(WTACFCPrsState~Age + Gender + Education +
CFCpercpt + CFCPref + CFCPrevUse + condtrlbr + Drvcomn
+ DrvrCosts + SocInflnc + TotDaycollect + Complx + Compblty +
Interests + InflcdWTACFC + (1|TotDaycollect),
data = FullDriverDataset, family = bernoulli(link = “logit”),
warmup = 1000, iter = 8000, seed = 125, chains = 4, prior = prior5,
control = list(adapt_delta = 0.999, max_treedepth = 20), cores = 2).

This model runs only 3 out of 4 chains and stops there!! it has spent over an hour after running the 3rd chain and nothing takes place. I reloaded, but it does the same thing. Kindly help!

max_treedepth is very high, so it may cause rather long runs of your model. What if you change it to 12?