Your requirements could not be resolved to an installable set of packages. Problem 1 - symfony/monolog-bundle v3.1.0 requires symfony/monolog-bridge ~2.7|~3.0 -> found symfony/monolog-bridge[v2.7.0-BETA1, ..., v2.8.52, v3.0.0-BETA1, ..., v3.4.47] but these were not loaded, likely because it conflicts with another require. - symfony/monolog-bundle[v3.1.1, ..., v3.2.0] require symfony/monolog-bridge ~2.7|~3.0|~4.0 -> found symfony/monolog-bridge[v2.7.0-BETA1, ..., v2.8.52, v3.0.0-BETA1, ..., v3.4.47, v4.0.0-BETA1, ..., v4.4.43] but these were not loaded, likely because it conflicts with another require. - symfony/monolog-bundle[v3.3.0, ..., v3.3.1] require symfony/monolog-bridge ~2.7|~3.3|~4.0 -> found symfony/monolog-bridge[v2.7.0-BETA1, ..., v2.8.52, v3.3.0-BETA1, ..., v3.4.47, v4.0.0-BETA1, ..., v4.4.43] but these were not loaded, likely because it conflicts with another require. - symfony/monolog-bundle v3.4.0 requires symfony/monolog-bridge ~3.4|~4.0 -> found symfony/monolog-bridge[v3.4.0-BETA1, ..., v3.4.47, v4.0.0-BETA1, ..., v4.4.43] but these were not loaded, likely because it conflicts with another require. - symfony/monolog-bundle[v3.5.0, ..., v3.6.0] require symfony/monolog-bridge ~3.4 || ~4.0 || ^5.0 -> found symfony/monolog-bridge[v3.4.0-BETA1, ..., v3.4.47, v4.0.0-BETA1, ..., v4.4.43, v5.0.0-BETA1, ..., v5.4.22] but these were not loaded, likely because it conflicts with another require. - symfony/monolog-bundle v3.7.0 requires symfony/monolog-bridge ~4.4 || ^5.0 -> found symfony/monolog-bridge[v4.4.0-BETA1, ..., v4.4.43, v5.0.0-BETA1, ..., v5.4.22] but these were not loaded, likely because it conflicts with another require. - symfony/monolog-bundle[v3.7.1, ..., v3.8.0] require symfony/monolog-bridge ~4.4 || ^5.0 || ^6.0 -> found symfony/monolog-bridge[v4.4.0-BETA1, ..., v4.4.43, v5.0.0-BETA1, ..., v5.4.22, v6.0.0-BETA1, ..., v6.4.0-BETA1] but these were not loaded, likely because it conflicts with another require. - Root composer.json requires symfony/monolog-bundle ^3.1 -> satisfiable by symfony/monolog-bundle[v3.1.0, ..., v3.8.0].