I have done various roles over many many years - developer, senior developer, technical lead etc.
From your question - it's quite obvious that your developers don't tell you stuff because they don't think you can help.
This may be because of 2 reasons.
- They don't think you have the power to fix things. However, I think this is unlikely because then you probably would know it & also the developers would have whined about it to you.
- You are the kind of person who when a developer comes to you with a problem, does one or more of the following things
- When they come to you with problems, you tell them - I like solutions not problems.
- You listen to them nicely & then task them with fixing the problem. You give them pep talk about what an honour it is for them be given the responsibility to fix the problem. Over time your guys understand that when they go to you with a problem, they will end up with extra work, so they don't come to you with problems.
- You deny it's a problem. You give convincing reasons for this. But as this keeps happening, over time your guys learn that there is no point approaching you with a problem.
- You say "Yes, I understand". You say this kind of stuff happens occasionally & there is nothing one can do. If this is a pattern, then again your guys understand it.
If it's any or all of the above, then you need to rectify it.