Martin, most regionals will balk at any number of perceived issues besides checkride busts or the proverbial skeletons in the closet. Some other factors may be

• skill or knowledge weakness exhibited at the interview
• race-gender-religion (EEO) mismatch to company needs
• age (old)
• perceived likely to resign soon
• personality
• background (ie. type of flying)
• credentials not in order

The operating phrase is "who will make us money with the least trouble". You may be an excellent pilot but also one who does not fit the company profile in any of a hundred ways. Airlines interview potential candidates for years on end and they collect tons of data. They have a clear idea whom they prefer.